Biomedical Engineering and Bioengineering Commons^™

Critical Shear Stress And Critical Flow Rates For Initiation Of Rilling, John E. Gilley, W. J. Elliot, J. M. Laflen, J. R. Simanton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was conducted to identify critical shear stress and critical flow rates required to initiate rilling on selected sites. The data used in this investigation were collected from soils located throughout the USA where crop residues had been removed, and moldboard plowing and disking had occurred. Runoff and soil loss measurements were made on sites where simulated rainfall was applied to preformed rills. Multiple regression analyses were used to relate critical shear stress values and critical flow rates to selected soil properties. The soil-based regression equations were found to provide reliable estimates. Information identified in this study will improve …

Drying Rate Constants For Yellow Dent Corn As Affected By Fatty Acid Ester Treatments, Curtis L. Weller, J. M. Bunn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Ethyl oleate and ethyl stearate solutions at various concentrations were used to treat corn samples prior to drying.

Property Modification Of Edible Wheat, Gluten-Based Films, A. Gennadios, Curtis L. Weller, R. F. Testin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Procedures were developed to produce edible wheat, gluten-based films. A film was produced as a standard. Five additional films were then produced by modifying the initial film-forming solution. Modifications included changing the plasticizer, partially substituting wheat gluten with soy protein isolate and corn zein, and incorporating two acetylated monoglyceride products. All films were characterized by measuring selected mechanical properties, and permeabilities to water vapor and to oxygen. Comparison of the films, in terms of their measured properties, indicates ways to improve the overall performance of the standard film as a potential packaging material. A main limitation of all of the …

Relative Humidity And Temperature Effects On Tensile Strength Of Edible Protein And Cellulose Ether Films, A. Gennadios, H. J. Park, Curtis L. Weller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effect of relative humidity and temperature on tensile strength of two types of protein-based [corn zein (CZ) and wheat gluten (WG)] and two types of cellulosic [methylcellulose (MC) and hydroxypropyl cellulose (HPC)] hydrophilic edible films was investigated.

Modification Of Physical And Barrier Properties Of Edible Wheat Gluten-Based Films, Aristippos Gennadios, Curtis L. Weller, Robert F. Testin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Edible films were produced from wheat gluten-based film-forming solutions. One film was produced as a control. Other types came from subjecting control films to three different soaking treatments. Three additional films were also produced by modifying the control film-forming solution. For all films, selected physical properties and permeability to water vapor and oxygen were measured. Comparisons indicated possible ways to improve the control film. All films were good oxygen barriers but limited water vapor barriers. Films containing hydrolyzed keratin had lower oxygen permeability (83%) and lower water vapor permeability (23%). Films containing mineral oil had lower water vapor permeability (25%). …

Chemical Tracing Techniques For Evaluating Rill Hydraulics, John E. Gilley, Eugene R. Kottwitz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Development of water erοsiοn and surface water quality control practices requires information concerning the hydraulic characteristics of upland areas. The relatively small flow rates normally found within rills make measurement of hydraulic parameters difficult. Chemical tracing procedures, originally developed for stream and river systems, have been successfully used to measure rill flow properties. A chemical tracer of known concentration is added to the rill and by knowing the degree of dilutiοn at a downstream sampling point, flow rate can be calculated. Rill flow velocity can be measured by determining the time required for a slug of tracer material to travel …

Sediment Delivery On Rill And Interrill Areas, John E. Gilley, D. C. Kincaid, W. J. Elliot, J. M. Laflen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Equations which relate sediment delivery to a power function of flow rate and slope gradient were calculated in this study. The data used to parameterize the calculations were obtained from sites where crop residues had been removed. and moldboard plowing and disking had occurred. Measurements of sediment delivery resulting from simulated rainfall were obtained from preformed rills and interrill areas. The equations provided reliable sediment delivery estimates for selected soils located throughout the United States. To use the sediment delivery equations, soil-related parameter values must be identified. Multiple regression analyses were performed to relate parameter values used in the equations …

Beginning Of Motion For Selected Unanchored Residue Materials, John E. Gilley, Eugene R. Kottwitz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Conservation tillage systems help to maintain residue materials from the previous crop on the soil surface. The potential for serious erosion may exist if crop residues are removed by overland flow. This study is conducted to identify the hydraulic conditions required to initiate residue movement by overland flow. Corn, cotton, peanut, pine needles, sorghum, sunflower, and wheat residue are placed in a flume on smooth and sand surfaces, and flow is then introduced in progressive increments. The discharge rate and flow velocity required to initiate residue movement are identified. Hydraulic measurements are used to calculate the ratio of critical flow …

Comparison Of Optimization Methodologies For Sustained-Yield Groundwater Pumping Planning In East Shore Area, Utah, Shu Takahashi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Combined simulation and optimization models, which are helpful for long-term groundwater planning of complex nonlinear aquifer systems, are developed using alternative modelling approaches. The models incorporate a representation of steady-state, quasi-three-dimensional head response to pumping within an optimization. An embedding model which describes exactly the nonlinear flow of an unconfined aquifer is presented. In contrast with the embedding models presented in the Utah State University Ground Water Model, it directly achieves the optimal solution without a "cycling." To address the nonlinearity of the flow system, response matrix models couple superposition with the cycling procedure. Their linear influence coefficients are generated …

Darcy-Weisbach Roughness Coefficients For Gravel And Cobble Surfaces, John E. Gilley, Eugene R. Kottwitz, Gary A. Wieman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A laboratory study is conducted to measure Darcy-Weisbach roughness coefficients for selected gravel and cobble materials. Varying rates of flow are introduced into a flume in which a given size class of gravel or cobble material is securely attached. Roughness coefficients are calculated from measurements of discharge rate and flow velocity. The laboratory data are used to develop regression equations for relating roughness coefficients to surface cover and Reynolds number. The regression relations, which are developed for values of the Reynolds number from approximately 500 to 16,000, are tested using hydraulic data collected on surfaces containing a distribution of size …

Microstructure Of Mica Glass-Ceramics And Interface Reactions Between Mica Glass-Ceramics And Bone, W. Holand, W. Gotz, G. Carl, W. Vogel

Cells and Materials

This review paper characterizes glass-ceramics containing mica as main crystal phase. The phase formation reactions in dependence of the chemical composition and the microstructure are shown. Microstructure of mica glass-ceramics has been studied by electron replica and scanning electron microscopic (SEM) techniques.

Mica glass-ceramics have previously been developed in Si02-B20rA120rMgO-F--base glasses. The material is machinable because of the precipitation of micas of fluorophlogopite-type. Also, a machinable glass-ceramic for dental applications was developed based on KMg2_5(Si40 10)F2-micas. We developed mica glass-ceramics in the Si02-Al20rMgO-NaiO-K20-F glass system. Phase formation within these glasses was observed by SEM. A double controlled nucleation and crystallization …

The Effect Of Polymethylmethacrylate Bone Cement Vibration On The Bone-Cement Interface, A. M. C. Thomas, D. J. W. Mcminn, M. Haddaway, I. W. Mccall

Cells and Materials

Low frequency vibration of polymethylmethacrylate (PMMA) bone cement reduces the viscosity of the cement by shear thinning. The effect of this low frequency vibration on the bone-cement interface was studied using microfocal radiography (MFR) and scanning electron microscopy (SEM). Effects were studied in-vitro and in-vivo. In-vitro, samples of Palacos low viscosity PMMA were placed on blocks of Kiel bone and vibrated. MFR and SEM demonstrated an improvement in the appearance of the bone-cement interface. In-vivo, PMMA was injected into the upper tibia of the dog. An assessment of the effect of high and low pressure injection, and the effect of …

Ultrastructural Assessment Of Lesion Development In The Collared Rabbit Carotid Artery Model, J. E. Beesley, A. C. Honey, J. F. Martin

Cells and Materials

Cellular reactions associated with the formation of lesions generated in the carotid artery of rabbits fed either normal or high cholesterol diets by the placement of a flexible, silastic collar around the artery, were studied by electron microscopy.

Endothelial cells remained as a monolayer throughout lesion development. The endothelial cell surface in both experimental and sham operated carotids, 4 hours and 8 hours after the initiation of the experiments, were covered with platelets and leukocytes. Neutrophils were present until 7 days in the arteries from within the collar of animals maintained on a normal diet, but only to 1 day …

Applications Of Fourier Transform Infrared (Ft-Ir) Microscopy To The Study Of Mineralization In Bone And Cartilage, Adele L. Boskey, Nancy Pleshko, Stephen B. Doty, Richard Mendelsohn

Cells and Materials

Knowledge of the phase, composition, and crystallite size and perfection of the mineral in normal and abnormally calcified tissues provides insight into the mechanism by which this mineral was deposited. These data also can be used to develop rational therapies for pathological conditions characterized by abnormal mineral deposition. As illustrated in this review, coupling of an optical microscope with a Fourier transform infrared (FT-IR) spectrophotometer permits the mapping at 20 μm spatial resolution of changes in mineral characteristics (content, particle size, composition) in the growth plate, in bone biopsies, in mineralizing cell culture systems, and in soft tissue calcifications. Based …

A Model For A Model: Pressure Jackets On Nude Mice With Implants Of Hypertrophic Scars, C. Ward Kischer, Jana Pindur

Cells and Materials

The hypertrophic scar, a consequence of deep surface injury, is peculiar to humankind. Subcutaneous implants of these tissues in nude mice provide a quasi - animal model for experimental use. An efficacious treatment to promote acceleration of maturation of the hypertrophic scar is controlled topical pressure produced by flexible dacron fabric wraps. Implants in the nude mouse provide a model for study of the effects of pressure. Preliminary results indicate that those implants in nude mice, responding favorably to pressure jackets, show changes consistent with those previously obtained in human studies. The collagen matrix shows reduced density and parallel layering …

Quantitative Scanning Electron Microscopy (Sem) To Study The Adhesion And Spreading Of Human Endothelial Cells To Surface-Modified Poly(Carbonate Urethane)S, C. James Kirkpatrick, Tillmann Otterbach, Dirk Anderheiden, Johannes Schiefer, Horst Richter, Hartwig Hartwig Hocker, Christian Mittermayer, Albert Dekker

Cells and Materials

The polymers currently in use as vascular prostheses are, in the native state, poor substrates for endothelial cell (EC) adhesion and growth. This has a negative effect on the success of pre-seeding regimes. One attempt to improve the polymer substrate is to covalently couple reactive molecules to the surface, which can be used as anchorage points for EC or serve as spacer molecule to couple biological signal molecules such as oligopeptides. We have used a digitized image analysis system coupled to a scanning electron microscope to study the adhesion and spreading of human venous EC to unmodified poly(carbonate urethane) (uPCU), …

Comparative Assessment Of The Cytotoxicity Of Various Substrates In Organ Culture And Cell Culture: A Scanning Electron Microscopy Study, J. L. Duval, R. Warocquier-Clerout, M. F. Sigot-Luizard

Cells and Materials

A comparative study of the behavior of chick embryo endothelial cells grown on various substrates was performed in order to establish the reliability and the limitation of both cell and organ culture methods. Following substrates were analyzed to compare these two different culture techniques: bovine serum albumin, pigskin gelatin and albumin + gelatin cross-linked by glutaraldehyde or carbodiimide, fibrin glue and negative control (Thermanox*). Parameters of cell growth and adhesion were calculated and compared with electron microscopic observations of cell morphology and of the extracellular matrix. Both culture methods provided complementary results and led to a similar classification of the …

Scanning Electron Microscopy Of The Bone Interface With Titanium, Titanium Alloy And Hydroxyapatite, R. D. Orr, J. D. De Bruijn, J. E. Davies

Cells and Materials

Screw implants of commercially pure titanium and titanium alloy together with rods of slip-cast dense hydroxyapatite were implanted transfemorally in young adult rats. The femora were harvested after fixation and freeze-fractured in liquid nitrogen to create two tissue fragments of each specimen. The first contained the implant while the second enabled examination of the tissue immediately adjacent to the implant. In all cases, the tissue abutting the implant was a cement line-like layer which separated the implant from the surrounding bone proper. Greater adherence of this interfacial tissue was demonstrated to hydroxyapatite samples compared with the titanium screws, while no …

Microstructural Changes In Retrieved Amalgam Restorations, Grayson W. Marshall Jr., D. D. Mccoy, John H. Kinney, Hugo Letzel, Sally J. Marshall

Cells and Materials

Many blended or dispersed phase high Cu amalgams show excellent clinical performance in long term clinical trials. However, little is known concerning the microstructural changes that occur during clinical use of these systems. This investigation sought to characterize some of the changes that occur in the Ag-Cu particles and their surrounding reaction zones based on a study by backscattered scanning electron microscopy (BSEM), energy dispersive spectroscopy and a new rnicroprobe technique called Colorad which assigns various colors to elements and element combinations and indicates changes in elemental concentration by changes in color value (brightness). Restorations were retrieved from clinical trials …

The Role Of Implant Surface Geometry On Mineralization In Vivo And In Vitro; A Transmission And Scanning Electron Microscopic Study, B. Chehroudi, J. Ratkay, D. M. Brunette

Cells and Materials

The purpose of th.is study was to examine the effect of substratum surface topography on bone formation in vivo and in vitro. Precise control over substratum topography was achieved using micromachining, a technique developed from the fabrication of microelectronic components. In the in vivo studies, titanium-coated epoxy replicas of micromachined surfaces were implanted subcutaneously in the parietal area of rats. After 6 weeks, bone-like tissue was found adjacent to some micromachined surfaces. Detailed observation of this tissue with the transmission electron microscope revealed osteoblast/osteocyte-like cells and a fully or partially mineralized collagenous matrix. Mineralized matrix and collagen bundles were …

Bone Regeneration Materials For The Mandibular And Craniofacial Complex, Jeffrey Hollinger, Anshumali Chaudhari

Cells and Materials

Due to different functional demands and vascularity, the mandibular and craniofacial complex require bone regenerating materials with physical and chemical properties that are different from long bone. However, certain common requirements to both locales must be addressed. Furthermore, reasons why the autograft and allogeneic bank bones are successful in regenerating bone need to be understood if the researcher is to develop satisfactory alternatives. The purpose of this paper is to review some of the requirements needed for bone regenerating materials for mandibular and craniofacial bone repair. In that effort, we have briefly described the autograft and allogeneic bank bones, animal …

The Tissue Responses To Tricalcium Phosphate Ceramics In Bone And Marrow, R. S. Archer, S. Downes, M. V. Kayser, S. Y. Ali

Cells and Materials

Calcium phosphate ceramics are described as "bioactive". Evidence of biological activity associated with calcium phosphate implanted in bone and marrow can be seen as changes in the morphology of the interfaces. In this in vivo model the sequence of progressive bone growth and bone merger with a dense calcium phosphate ceramics were examined by light and transmission electron microscopy. A spectrum of tissue responses to dense tricalcium phosphate ceramics was observed at intervals over a six week period. It is now well established that calcium phosphate ceramics permit bone ingrowth with little or no immunological response; however, a layer of …

Fine Structure Of Remodeling Sites On Iliac Cancellous Bone In Senile Osteoporosis: A Study By Scanning Electron Microscopy Using An Improved Organic Specimen Preparation Method, Toshihiko Takita, Tomonori Naguro, Kichizo Yamamoto

Cells and Materials

We improved on the organic specimen preparation method in order to investigate the details of the functional state of bone in osteoporosis at high magnification level. The usefulness and possibilities of this method are discussed showing fine structural images of remodeling sites. Iliac bones of senile osteoporotic patients obtained by transilial biopsies were studied by scanning electron microscopy (SEM) using the improved preparation method. Excepting the region near the corticoendosteal surface, most of the iliac cancellous bone was composed of thin rod-shaped trabeculae. Remodeling sites on trabeculae appeared as concavities of various sizes and were easily distinguished from inert surfaces. …

Clinical Applications Of Recombinant Gene Technology: Bone And Cartilage Repair, Thomas A. Einhorn

Cells and Materials

Over the past decade, the field of molecular biology has given rise to the development of the applied discipline of molecular medicine. Based on recent developments using recombinant gene technology, genetic mapping analysis and other investigational tools, the physician and surgeon is now ready to begin using those instruments in the diagnosis and treatment of musculoskeletal disease. This article reviews the history of scientific exploration in recombinant gene technology as it applies to bone and cartilage repair. Clinical cases are presented to show how the fruits of scientific knowledge may be brought to bear on some of the more challenging …

Patency Of Small Caliber, Superhydrophobic E-Ptfe Vascular Grafts; A Pilot Study In The Rabbit Carotid Artery, J. M. Schakenraad, I. Stokroos, H. Bartels, H. J. Busscher

Cells and Materials

e-PTFE vascular grafts (Gore, internal diameter 1.5 mm, pore size 30 μm) were luminally treated by ionbeam etching followed by oxygen glow-discharge, to obtain a superhydrophobic luminal surface. Water contact angles of thus modified sheet material were 140-150°, which is significantly higher than on non-treated sheet PTFE (109°). These modified vascular grafts were implanted in the rabbit carotid artery, using an end to end anastomotic technique. After two hours, the grafts were still patent and the wounds were closed. One week after the implantation, the prostheses were still patent. Subsequently, the grafts were harvested and prepared for light microscopy, transmission …

Reactogenicity Of Biomaterials As Studied By Biochemical, Morphological And Ultrastructural Techniques, Leonid I. Slutskii, Natalya A. Sevastjanova, Ivetta L. Ozolanta, Irina V. Kuzmina, Laimdota E. Dombrovska

Cells and Materials

Reactogenicity is a characteristic of biocompatible materials that provokes the reparative and proliferative reaction of connective tissues, a compulsory stage of which is inflammation. Thus, reactogenicity studies should include experiments in vivo. A quantitative assessment of reactogenicity can be obtained by subcutaneous implantation of standard olive-shaped specimens covered by the biomaterial under study followed by biochemical, histological and scanning electron microscopical studies of the capsule developing around the implant. Reactogenicity of surgical threads is evaluated by semiquantitative histological analysis of the wound healing process after suture application. Biomaterial reactogenicity can be modified by changing the structure of the surface and …

Scanning Electron Microscopy Study Of Biofilms On Silicone Voice Prosthesis, T. R. Neu, F. Dijk, G. J. Verkerke, H. C. Van Der Mei, H. J. Busscher

Cells and Materials

Patients after laryngectomy often receive silicone made voice prostheses fot speech rehabilitation. The prosthesis is inserted in a shunt between the trachea and the digestive tract. As the prosthesis is placed in a nonsterile environment it becomes rapidly colonized by microorganisms eventually leading to failure and frequent exchange of the implant. In this study, explanted "Groningen Button" silicone voice prostheses were used to investigate by scanning electron microscopy the biofilm developing on the implant. Two main types of microbial colonization forms could be distinguished. Firstly, macroscopically visible, single colonies dominating on the esophagus side of the prosthesis were found, which …

Investigation On The Collagen Fiber Network In Human Dental Tissues - Transmission And Scanning Electron Microscopy, C. Marchetti, P. Menghini, C. Piacentini

Cells and Materials

The collagen fiber component of pulp, dentine and cementum, has been studied by isolating it from the inorganic component and the organic non-collagen matrix. This study was carried out on healthy molar and premolar adult teeth. Following demineralization all of the non-collagenous components of the tooth were removed by sequential treatment with H202, with different concentrations of trypsin and with EDTA. The transmission (TEM) and scanning (SEM) electron microscopy investigation confirmed that such a technique is an accurate method for isolating the collagen fibers while preserving their position and their ultrastructure in the dental tissue. The use of TEM and …

Scanning Electron Microscope Observation Of Lubricious Polymer Surface For Medical Use, Hiroyuki Inoue, Yoshikimi Uyama, Emiko Uchida, Yoshito Ikada

Cells and Materials

A peculiar textured structure was found by scanning electron microscopic (SEM) observation on polymer films surface-grafted with water-soluble polyacrylamide and poly(N,N-dimethylacrylamide) after exposure to ozone. The grafted surface became very hydrophilic and highly lubricated when brought into contact with water, due to hydration of the grafted surface layer. Unless water was present, the surface did not become slippery at all. SEM of the grafted surface revealed different profiles, depending on the graft density as well as the process of drying prior to the SEM observation. There was no significant difference between the virgin and the surface-grafted film, when air-dried under …

Interaction Of Liposomal Drug Delivery Systems With Cells And Tissues: Microscopic Studies, M. Foldvari, G. T. Faulkner, C. Mezei, M. Mezei

Cells and Materials

Liposomes , as drug carriers, can be administered into the body by several routes e.g. intravenously, intraperitoneally, intramuscularly, intratracheally and topically among others. Radiolabelled markers are suitable to monitor the distribution and elimination of liposomes, but the tissue deposition of intact liposomes, the mode and sites of drug release from the liposomes and liposome-cell interactions cannot be investigated morphologically. Microscopic techniques could provide information regarding the intact state of liposomes and possibly the dynamics of liposomes in tissues provided that they can be identified with certainty in vivo. This is a formidable problem and in spite of several attempts, there …