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Articles 1 - 30 of 35
Full-Text Articles in Biological Engineering
Area Conservation Tillage Meetings-A Successful Educational Program, Elbert C. Dickey, Paul J. Jasa, David P. Shelton, Robert Grisso, Keith Glewen
Area Conservation Tillage Meetings-A Successful Educational Program, Elbert C. Dickey, Paul J. Jasa, David P. Shelton, Robert Grisso, Keith Glewen
Biological Systems Engineering: Papers and Publications
Interest in conservation tillage began to increase in the early 1980s, and farmers wanted information on how to adopt and manage various tillage and planting systems. Area conservation tillage meetings were developed by the University of Nebraska Cooperative Extension to provide the needed information on a regional basis. Local extension agents and Soil Conservation Service personnel helped extension specialists determine program content. The multidisciplinary meetings included farmer presentations and allowed space and time for commercial exhibits. About 80% of respondents to meeting evaluations indicated they planned to change their tillage practices as a result of the information presented.
A Conservation Tillage Educational Program, Elbert C. Dickey, Paul J. Jasa, David P. Shelton
A Conservation Tillage Educational Program, Elbert C. Dickey, Paul J. Jasa, David P. Shelton
Biological Systems Engineering: Papers and Publications
An educational program was conducted to enhance the adoption of conservation tillage practices in targeted areas to reduce soil erosion and on-farm fuel use. Traditional extension methods such as meetings, field days, demonstrations, and plots were used extensively. In addition, the following nontraditional educational methods were used to achieve project objectives: targeting high priority areas, local program guidance committees, surveys to evaluate perceptions and use of conservation tillage, employment of extension assistants to work in the target areas, use of a rainfall simulator to demonstrate the effectiveness of residue cover in reducing erosion, and small group or "coffee shop" meetings …
Roughness Coefficients For Selected Residue Materials, John E. Gilley, Eugene R. Kottwitz, Gary A. Wieman
Roughness Coefficients For Selected Residue Materials, John E. Gilley, Eugene R. Kottwitz, Gary A. Wieman
Biological Systems Engineering: Papers and Publications
Analysis of surface runoff on upland areas requires identification of roughness coefficients. A laboratory study is conducted to measure Darcy-Weisbach and Manning roughness coefficients for corn, cotton, peanut, pine needles, sorghum, soybeans, sunflower, and wheat residue. Varying rates of flow are introduced into a flume in which selected amounts of residue are securely attached. Roughness coefficients are calculated from measurements of discharge rate and flow velocity. The laboratory data are used to derive regression equations for relating roughness coefficients to Reynolds number and either percent residue cover or residue rate. Separate equations are developed for Reynolds number values from 500 …
Hydraulic Roughness Coefficients As Affected By Random Roughness, John E. Gilley, S. C. Finkner
Hydraulic Roughness Coefficients As Affected By Random Roughness, John E. Gilley, S. C. Finkner
Biological Systems Engineering: Papers and Publications
Random roughness parameters are used to characterize surface microrelief. In this study, random roughness was determined following six selected tillage operations. Random roughness measurements agreed closely with values reported in the literature.
Surface runoff on upland areas is analyzed using hydraulic roughness coefficients. Darcy-Weisbach and Manning hydraulic roughness coefficients were identified in this investigation on each soil surface where random roughness values were determined. Hydraulic roughness coefficients were obtained from measurements of discharge rat巳and flow velocity.
The experimental data were used to derive regression relationships which related Darcy-Weisbach and Manning hydraulic roughness coefficients to random roughness and Reynolds number. Random …
Preservation Of The Cell-Biomaterial Interface At The Ultrastructural Level, J. M. Schakenraad, J. A. Oosterbaan, E. H. Blaauw
Preservation Of The Cell-Biomaterial Interface At The Ultrastructural Level, J. M. Schakenraad, J. A. Oosterbaan, E. H. Blaauw
Cells and Materials
Studying the tissue-biomaterial interface at the ultrastructural level is not without problems. Dissolution of the biomaterial in one of the dehydration or embedding media causes holes and shatter during sectioning or dislodgement of the biomaterial. The fine tuning of the hardness of both biomaterial and embedding medium, as well as the introduction of butyl-2,3- epoxypropylether as an intermediate between the dehydration series and the Epon resin , improving the impregnation , will solve many of the problems mentioned. With this improved technique good results were obtained with materials ranging from teflon, poly(Lactic acid) and polyurethanes to tissue culture polystyrene. No …
Deposition And Resorption Of Calcified Matrix In Vitro By Rat Marrow Cells, J. E. Davies, R. Chernecky, B. Lowenberg, A. Shiga
Deposition And Resorption Of Calcified Matrix In Vitro By Rat Marrow Cells, J. E. Davies, R. Chernecky, B. Lowenberg, A. Shiga
Cells and Materials
Rat bone marrow derived cells were cultured using a-Minimal Essential Medium supplemented with antibiotics, ascorbic acid and !3-glycerphosphate in the presence of 10-8M dexamethasone, on polystyrene and hydrophilic fluorocarbon substrata for periods of 2 - 4 weeks. During this time, a large yield of bone nodules was achieved and the elaborated tissue was examined by both scanning and transmission electron microscopy. The matrix produced by the cells contacting the underlying substratum was an afibrillar, globular, calcified material which formed a layer approximately 0.5μm thick. The calcium and phosphorus content of this material was confirmed by energy dispersive X-ray dot mapping …
Analysis Of Protein Adsorption On Retrieved Human Vascular Grafts Using Immunogold Labelling With Silver Enhancement, N. P. Ziats, N. S. Topham, D. A. Pankowsky, J. M. Anderson
Analysis Of Protein Adsorption On Retrieved Human Vascular Grafts Using Immunogold Labelling With Silver Enhancement, N. P. Ziats, N. S. Topham, D. A. Pankowsky, J. M. Anderson
Cells and Materials
The adsorption of proteins on biomedical materials such as vascular grafts is important in modulating thrombosis, one eventual cause of vascular graft failure. We have identified proteins expressed on the surfaces of retrieved vascular grafts to determine if certain proteins were present at the end stage of vascular failure. Scanning electron microscopic analysis of protein adsorption on the surfaces of retrieved vascular prostheses was determined using antibodies to human blood proteins fibrinogen, fibronectin, Hageman factor (factor XII) and factor VIII/von Willebrand Factor. The detection of these proteins on the blood contacting surface was evaluated by immunogold labelling with protein A-gold …
Peripheral Nerve Bridges For Central Nervous System Regeneration, Silvio Varon, Theo Hagg, H. Lee Vahlsing, Marston Manthorpe
Peripheral Nerve Bridges For Central Nervous System Regeneration, Silvio Varon, Theo Hagg, H. Lee Vahlsing, Marston Manthorpe
Cells and Materials
A neuronotrophic hypothesis for the adult central nervous system (CNS) has been increasingly supported by in vivo studies of Nerve Growth Factor (NGF) impacts on adult rat CNS cholinergic neurons. We have extended these investigations to NGF effects on cholinergic axonal regeneration in an adult rat septo-hippocampal model. A fimbriafornix lesion deprives the dorsal hippocampal formation (HF) of its cholinergic afferents and provides a cavity into which sciatic nerve segments can be implanted to serve as regeneration bridges from septum to HF. Septa! cholinergic fibers enter and course through fresh cell-containing nerve bridges to attain a maximal number by the …
Evaluation Of The Images Of Specular Microscopy Of The Cells On Implanted Intraocular Lenses In Vivo, Kiyoshi Okada, Keiko Takahashi, Hiroaki Sagawa, Kuniomi Abe
Evaluation Of The Images Of Specular Microscopy Of The Cells On Implanted Intraocular Lenses In Vivo, Kiyoshi Okada, Keiko Takahashi, Hiroaki Sagawa, Kuniomi Abe
Cells and Materials
Specular microscopy , an optical method to study the anterior segment of the eye, was applied to observe the cells on implanted intraocular lenses in vivo. The images from specular microscopy were evaluated by comparing the morphology of the same cells on intraocular lenses implanted in rabbit eyes by specular microscopy , light microscopy and scanning electron microscopy (SEM). The time lapse study in living human eyes and the optical evaluation of jts interference images were performed to elucidate its image formation.
The same giant cells, as observed in vivo by specular microscopy, proved to be multinucleated cells. It …
Interactions Of Bacteria And Amoebae With Ocular Biomaterials, Thomas John
Interactions Of Bacteria And Amoebae With Ocular Biomaterials, Thomas John
Cells and Materials
The use of biomaterials in periocular and intraocular sites has resulted in some ocular inflammations and infections which can result in vision-threatening ocular disease. This review addresses bacterial interactions with, and adherence to ocular biomaterials such as soft contact lenses, surgical suture materials, and intraocular lenses. In addition, adherence of Acanthamoeba to soft contact lenses is described, and the role of these lenses in the development of Acanthamoeba keratitis is discussed.
Dusts Produced During Cutting Of Modern Splinting Bandages, R. Wytch, D. W. Gregory, R. Clayton, D. Wardlaw
Dusts Produced During Cutting Of Modern Splinting Bandages, R. Wytch, D. W. Gregory, R. Clayton, D. Wardlaw
Cells and Materials
Previous work carried out by the authors (Wytch et al ., 1988a) has shown that airborne dust generated during removal of orthopaedic casts with a power saw could represent a respiratory hazard. Further work has been carried out on all types of splinting bandage currently available in the United Kingdom to assess the potential dust hazard when sawing these materials. It has been shown that although plaster of Paris bandage produces significant concentrations of airborne dust, most of the polyurethane-impregnated fabric bandages generate extremely low levels of dust and in the case of the non-glass fabrics, the level is insignificant. …
Scanning Electron Microscopic Evaluation Of The Fractured Surfaces Of Canine Calculi From Substrata With Different Surface Free Energy, H. M. W. Uyen, W. L. Jongebloed, H. J. Busscher
Scanning Electron Microscopic Evaluation Of The Fractured Surfaces Of Canine Calculi From Substrata With Different Surface Free Energy, H. M. W. Uyen, W. L. Jongebloed, H. J. Busscher
Cells and Materials
The strength of adhesion between dental calculus and enamel or dentin surfaces determines the ease with which the calculus can be removed by brushing or professional dental treatment. In this study, we examined the adhesion of canine calculi formed on substrata with different surface free energies (sfe) and roughness by means of scanning electron microscopy. In 4 beagle dogs fenestrated crowns were made on the upper fourth premolars. Subsequently, facings of glass (sfe = 120 mJ. m-2), bovine enamel (sfe = 85 mJ.m-2), bovine dentin (sfe = 92 mJ.m-2), polymethyl-methacrylate (PMMA, sfe = 56 mJ.m-2) and polytetrafluorethylene (PTFE, sfe = …
Polylysine Stimulation Of Ectopic Cartilage Formation, Rocky S. Tuan, Dina M. Turchi, David S. Kreitzer
Polylysine Stimulation Of Ectopic Cartilage Formation, Rocky S. Tuan, Dina M. Turchi, David S. Kreitzer
Cells and Materials
Cartilage development, or chondrogenesis, is a process which involves the condensation of prechondrogenic mesenchymal cells, followed by the expression of the cartilage phenotype characterized by the biosynthesis of cartilage-specific, extracellular matrix components. We have previously shown that the cationic biopolymer, polylysine (PL), is able to stimulate chondrogenesis by embryonic limb bud mesenchymal cells in vitro. In this study, we have evaluated the chondrogenesis-stimulating activity of PL in vivo using an experimental system consisting of chick embryonic muscle explants, which were grafted onto the chorioallantoic membrane of chick embryos maintained in long-term shell-less culture. The muscle grafts were treated with PL …
A Versatile, Low Toxicity Glycol Methacrylate Embedding Medium For Use In Biological Research, And For Recovered Biomaterials Prostheses, Peter O. Gerrits, Bernhard Eppinger, Harry Van Goor, Richard W. Horobin
A Versatile, Low Toxicity Glycol Methacrylate Embedding Medium For Use In Biological Research, And For Recovered Biomaterials Prostheses, Peter O. Gerrits, Bernhard Eppinger, Harry Van Goor, Richard W. Horobin
Cells and Materials
Methods for preparing standardized glycol methacrylate (GMA) based embedding media for use in light microscopy in a rational, precise and reproducible manner are described. The application of these procedures resulted in a versatile, low toxicity GMA embedding medium.
GMA embedding medium and resin blocks were tested utilizing a variety of physico-chemical techniques, namely: gas chromatography, determination of the maximum temperature reached during polymerization, the time taken to reach the maximum temperature, hardness testing, determination of the glass transition temperature, and measurement of the dimensional changes following section stretching and mounting at various temperatures. Data obtained from these techniques enabled a …
Fracture Toughness And Fractography Of Dental Ceramics, H. J. Mueller
Fracture Toughness And Fractography Of Dental Ceramics, H. J. Mueller
Cells and Materials
Chevron-notch short-rod fracture toughness (KIv) and scanning electron microscopy analyses of leucite-, tetrasilicic fluormica-, and alumina- reinforced dental ceramics and control materials were investigated. Short-rod fracture toughness is a measure of the bulk resistance to crack propagation but not of the surface resistance to crack initiation. Results indicated significant differences in KIv among the following six groups (from lowest to highest (a) Dicor and Optec, (b) Optec, Excelco's Incisal, Macor and Excelco's Gingival, (c) Excelco's Brush-O-Paque, (d) Vitadur-N core, (e) Coming's 9606 glass-ceramic, and (t) Vita Hi Ceram. Good agreement occurred with published data for Macor and 9606. Comparisons of …
Stereoscopic Analysis Of Trabecular Bone Orientation In Proximal Human Tibias, K. N. Bachus, M. K. Harman, R. D. Bloebaum
Stereoscopic Analysis Of Trabecular Bone Orientation In Proximal Human Tibias, K. N. Bachus, M. K. Harman, R. D. Bloebaum
Cells and Materials
The three-dimensional orientation of trabeculae is a key factor in determining the load carrying capabilities of cancellous bone. Previous biomechanical studies have shown that proximal tibias resected parallel to the articulating surface are stronger and stiffer than the contralateral tibias resected perpendicular to the long axis of the bone. However, morphologic evidence was not provided to help explain the mechanical differences.
To determine the orientation of the trabeculae in the medial condyle for both parallel cut and perpendicular cut specimens, a scanning electron microscope and stereoscopic techniques were used. Data showed that tibias cut parallel to the articular surface had …
Subsoiling, Contouring, And Tillage Effects On Erosion And Runoff, Paul J. Jasa, Elbert C. Dickey
Subsoiling, Contouring, And Tillage Effects On Erosion And Runoff, Paul J. Jasa, Elbert C. Dickey
Biological Systems Engineering: Papers and Publications
A study to evaluate the effectiveness of subsoiling on reducing soil erosion and water runoff from continuous com production was conducted. A rotating boom rainfall simulator was used on replicated treatments having either preplant in-row subsoiling or postplant between-row subsoiling used in both tilled and untilled surface conditions. Tilled and untilled treatments without subsoiling were used as checks. These six treatments were used up-and-downhill and on the contour.
Subsoiling reduced the rate of water runoff but did not significantly reduce the soil erosion rate after equilibrium had been reached between water application and runoff rates. Surface condition and farming direction …
Fertilization Of Crops With Feedlot Manure, Elbert C. Dickey, Gerald Bodman
Fertilization Of Crops With Feedlot Manure, Elbert C. Dickey, Gerald Bodman
Biological Systems Engineering: Papers and Publications
The application of animal manure to farmland is an appropriate and environmentally sound management practice for most feedlot operators. Land application returns nutrients from manure to the soil and helps build and maintain soil fertility. In addition to containing nitrogen, phosphorus and potassium, manure contains trace "elements such as calcium, magnesium, iron and zinc. Manure has also been shown to improve soil tilth, increase water-holding capacity, lessen wind and water erosion and improve aeration. Land application of manure should be viewed as a means to utilize crop nutrients present in the manure for crop production rather than utilizing the land …
Performance Of Seedigated And Conventionally Planted Crops, W. S. Leander Jr., Derrel L. Martin, James R. Gilley
Performance Of Seedigated And Conventionally Planted Crops, W. S. Leander Jr., Derrel L. Martin, James R. Gilley
Biological Systems Engineering: Papers and Publications
Seedigation is the use of a moving sprinkler irrigation system to broadcast seeds on the soil surface. Seed germination, plant characteristics and yield for grain sorghum, winter wheat and soybeans that were seedigated and conventionally planted are compared. When the seeding rates for seedigation were increased above that for conventional planting, and adequate moisture was available for germination, grain sorghum and wheat seedigated on tilled surfaces produced yields similar to conventionally planted crops. Seedigation of soybeans into fallow conditions, or when used as a relay crop, was unsuccessful. Shallow disking following seedigation did not improve germination or yield of grain …
A Cooperative Educational Program To Reduce Soil Erosion, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, David A. Biere, Susan Smydra Krotz
A Cooperative Educational Program To Reduce Soil Erosion, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, David A. Biere, Susan Smydra Krotz
Biological Systems Engineering: Papers and Publications
Eastern Nebraska, especially the northeastern portion, has a history of severe soil erosion, due in part to a predominance of steep slopes and highly erodible soils (12). While the average annual allowable soil loss ("T" value) for most of these soils is five tons per acre, some fields have annual soil erosion rates that exceed 100 tons per acre. The loss of topsoil is critical, of course, but erosion from cropland also results in the removal of fertilizers and pesticides, which degrades water quality.
Even though farmers are generally aware that soil erosion is a national problem, many …
Enhancing Soil Conservation Practice Adoption With Targeted Educational Programs, Elbert C. Dickey, David P. Shelton, Paul J. Jasa
Enhancing Soil Conservation Practice Adoption With Targeted Educational Programs, Elbert C. Dickey, David P. Shelton, Paul J. Jasa
Biological Systems Engineering: Papers and Publications
Two independent, but closely related, grant funded educational programs were developed and implemented to reduce soil erosion in selected areas of eastern Nebraska. Traditional extension programming methods as well as other more non-traditional approaches were used extensively to enhance soil conservation practice adoption. In one program, encompassing 220 000 ha (540,000 acre) of cropland, annual soil erosion was reduced by 2.3 million t (2.5 million ton) and annual fuel savings of 1.5 million L (390,000 gal) were achieved through a reduction in the number of tillage operations. In the second project, more than 93 000 m (305,000 ft) of terraces …
Estimating Percent Residue Cover Using The Line-Transect Method, David P. Shelton, Elbert C. Dickey, Roger Kanable, Stewart W. Melvin, Charles A. Burr
Estimating Percent Residue Cover Using The Line-Transect Method, David P. Shelton, Elbert C. Dickey, Roger Kanable, Stewart W. Melvin, Charles A. Burr
Biological Systems Engineering: Papers and Publications
Estimating Percent Residue Cover Using the Line-Transect Method
The line-transect method is one of the easiest method to use in the field to determine the percent residue cover on the surface. Accurate measurement is necessary to determine if enough cover is present to comply with the conservation plan.
The following is a step-by-step procedure for using the line-transect method to measure the percentage of residue cover.
Step 1
Use a 100-foot or 50-foot measuring tape for measuring residue cover. Other measuring length or even knotted ropes can be used if the appropriate multiplication factor is used to calculate the percentage. …
Residue Management To Control Soil Erosion By Water, Elbert C. Dickey, David P. Shelton, Paul J. Jasa, Michael C. Hirschi
Residue Management To Control Soil Erosion By Water, Elbert C. Dickey, David P. Shelton, Paul J. Jasa, Michael C. Hirschi
Biological Systems Engineering: Papers and Publications
The Erosion Process
Erosion of topsoil begins when water detaches individual soil particles from clod and other soil aggregates. A single raindrop may seem insignificant, yet collectively, raindrops strike the ground with surprising force. During an intense storm, rainfall can loosen and detach up to 100 tons of soil per acre and can be especially erosive when residue mulch or vegetation are not present to absorb their impact.
Two problems often occur during rainstorms. The rate of rainfall can exceed the rate at which water can enter the soil and raindrop impact forces can partially seal the soil surface. In …
Peripheral Nerve Regeneration Within Tubular Prosthesis: Effects Of Laminin And Collagen Matrices On Cellular Ingrowth, Ivar J. Kljavin, Roger D. Madison
Peripheral Nerve Regeneration Within Tubular Prosthesis: Effects Of Laminin And Collagen Matrices On Cellular Ingrowth, Ivar J. Kljavin, Roger D. Madison
Cells and Materials
Bridging a severed peripheral nerve with a tubular conduit, "entubulation repair" , allows manipulation of the microenvironment encountered by regenerating axons. In the present study, we placed the ends of severed mouse sciatic nerves into nonpermeable Tygon tubes to bridge a 4 mm nerve gap. The tube lumen was filled with either a collagen or laminin matrix. The matrices formed a stable 3-D structure connecting both proximal and distal stumps, and provided a scaffolding for the regenerating axons and their supporting cells. We examined with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and light microscopy, the initial events of …
Primary Bone Formation In Porous Hydroxyapatite Ceramic: A Light And Scanning Electron Microscopic Study, M. Okumura, H. Ohgushi, S. Tamai, E. C. Shors
Primary Bone Formation In Porous Hydroxyapatite Ceramic: A Light And Scanning Electron Microscopic Study, M. Okumura, H. Ohgushi, S. Tamai, E. C. Shors
Cells and Materials
Porous hydroxyapatite ceramics combined with rat marrow cells were implanted subcutaneously in the back of syngeneic Fischer rats . Fluorochrome-labeling (calcein, tetracycline) was performed post-operatively and the ceramics were harvested 4 weeks after implantation. Undecalcified thin sections of the implants were observed under light microscopy or fluoromicroscopy and the corresponding areas were also analyzed in a scanning electron microscope connected to an electron probe microanalyzer (SEM-EPMA). Many pore areas of the ceramics showed bone and osteoid formation together with active osteoblasts. The bone formation began directly on the surface of the ceramic and proceeded in a centripetal direction towards the …
A Simple Method For Ultrastructural Evaluation Of Fragile Collagenous Biomaterials, Arthur J. Wasserman, Yasushi P. Kato, Frederick H. Silver
A Simple Method For Ultrastructural Evaluation Of Fragile Collagenous Biomaterials, Arthur J. Wasserman, Yasushi P. Kato, Frederick H. Silver
Cells and Materials
No abstract provided.
Surface Modification Of Polymers To Permit Endothelial Cell Growth, C. James Kirkpatrick, Detlef Mueller-Schulte, Marc Roye, Guenter Hollweg, Claudia Gossen, Horst Richter, Christian Mittermayer
Surface Modification Of Polymers To Permit Endothelial Cell Growth, C. James Kirkpatrick, Detlef Mueller-Schulte, Marc Roye, Guenter Hollweg, Claudia Gossen, Horst Richter, Christian Mittermayer
Cells and Materials
The interaction between endothelial cells (EC) and polymers has become relevant to medicine as a result of attempts to improve the biocompatibility of vascular prostheses. In man, endothelialization is minimal, so that vascular surgeons have attempted to pre-seed vascular grafts with autologous EC. The poor results of EC seeding of commonly used materials for vascular grafts, such as expanded polytetrafluoroethylene (ePTFE) or woven polyester (Dacron) has led to attempts to modify the surface of these and other polymers. Three principal modification techniques have been employed : 1. adsorption of bioactive molecules from applied solutions. Examples are fibronectin, collagen types I …
Composite Filler Characterization By Scanning Electron Microscopy, Image Analysis And Thermogravimetry, J. Vaidyanathan, T. K. Vaidyanathan
Composite Filler Characterization By Scanning Electron Microscopy, Image Analysis And Thermogravimetry, J. Vaidyanathan, T. K. Vaidyanathan
Cells and Materials
The morphological and compositional characterization of the filler particles in selected dental composites has been accomplished by a combination of backscattered electron imaging, digital imaging , energy dispersive X-ray analysis and thermogravimetry. Backscattered electron images provide excellent composition contrast between the filler and the matrix in this analysis . Qualitative energy dispersive spectroscopy was used to classify the filler composition in the composites studied. The digital imaging technique of feature analysis was utilized to quantitatively characterize the particle morphological parameters and their distributions. Several parameters were determined of which the particle area, breadth, height and Waddel diameter are emphasized. Particle …
Adhesion Of Staphylococci To Breast Prosthesis Biomaterials: An Electron Microscopic Evaluation, T. A. Fassel, J. E. Van Over, C. C. Hauser, C. E. Edmiston, J. R. Sanger
Adhesion Of Staphylococci To Breast Prosthesis Biomaterials: An Electron Microscopic Evaluation, T. A. Fassel, J. E. Van Over, C. C. Hauser, C. E. Edmiston, J. R. Sanger
Cells and Materials
Gram-positive coagulase-negative staphylococci have been implicated in breast prosthesis infection. Staphylococcus au re us, Staphylococcus epidermidis, and Staphylococcus hominis strains were examined for adhesion and proliferation morphology to polyurethane foam and smooth silicone rubber prosthetic biomaterials. Ruthenium red, alcian blue and ruthenium red-lysine in en bloc procedures were applied to optimally visualize the polysaccharide slime. Ruthenium red processing resulted in observation of additional outer material close to the cell wall, more than seen in the absence of cationic reagent. Alcian blue preserved fibrous or netlike strands or meshworks of material. Ruthenium red-lysine preserved considerable amounts of slime covering the cocci …
Ultrastructural Study Of Bone Formation On Synthetic Hydroxyapatite In Osteoblast Cultures, J. M. Sautier, J. R. Nefussi, N. Forest
Ultrastructural Study Of Bone Formation On Synthetic Hydroxyapatite In Osteoblast Cultures, J. M. Sautier, J. R. Nefussi, N. Forest
Cells and Materials
Collagenase isolated rat calvaria cells forming a mineralized matrix in vitro were cultured in the presence of synthetic hydroxyapatite. Interactions between bone cells and hydroxyapatite biomaterial were followed by transmission electron microscopy. The appearance of a granular, collagen free, electron-dense layer at the periphery of the material was noted initially. Progressively, an amorphous, granular material formed and extended between the hydroxyapatite aggregates. Osteoblastic cells then synthesized an osteoid matrix which mineralized on the first formed granular collagen free layer, following a classical pattern of calcification . Demineralization of ultrathin sections confirmed the presence of this interface between the material and …