Engineering Commons^™

Experimental Induction Of Odontoblast Differentiation And Stimulation During Preparative Processes, H. Lesot, C. Begue-Kirn, M. D. Kubler, J. M. Meyer, A. J. Smith, N. Cassidy, J. V. Ruch

Cells and Materials

In vivo implantation experiments have shown that ethylenediaminetetraaceticacid(EDTA)-soluble frac tions of dentin stimulate reparative dentinogenesis . When isolated embryonic dental papillae were cultured in the presence of these dentin constituents, odontoblast cytological and functional differentiation could be initiated and maintained in the absence of an enamel organ. These effects were attributed to the presence of TGF-/1- related molecules [TGF-/11 or bone morphogenetic protein -2a (BMP-2a)] which had to be used in combination with an EDT A-soluble fraction of dentin in order to specifically affect competent preodontoblasts . These EDT A-soluble constituents present in dentin could be replaced by heparin or …

Calcification Of Liposomes And Red Cell Ghosts In Vitro And In Vivo, Kookmin M. Kim

Cells and Materials

To study the role of membranous phospholipids in calcification , liposomes made of phosphatidylserine and red blood cell ghosts (RBCG) prepared from rat and canine blood were incubated in minimal essential medium (MEM) with 2 .5 mM (mmol/l) calcium and 1.3 mM phosphate, pH 7.4 (MEM-2.5), and homologous (rat) or autologous (canine) plasma filtrate (serum) at 37°C for up to 1 week. Calcification was determined by electron probe microanalysis , electron diffraction, and depletions of calcium and phosphate from MEM-2.5 and sera. Liposomes and rat-RBCG incubated in MEM-2.5 and serum calcified in a week, whereas isolated collagen and elastin did …

Interaction Of Ciprofloxacin Loaded Liposomes With Pseudomonas Aeruginosa Cells, R. Nicholov, A. E. Khoury, A. W. Bruce, F. Dicosmo

Cells and Materials

An antibiotic delivery system has been developed using ciprotloxacin (CIPRO) encapsulated within sonicated unilamellar vesicles (SUV) of different lipid compositions composed of dipalmitoylphospatidylcholine (DPPC), L-aphosphatidylcholine (PC), phosphatidylethanolamine (PEA) and cholesterol (CHOL). The interaction of SUV (i.e. liposomes) with Pseudomonas aeruginosa (Tl 2977) cells was studied and the effect of the liposome encapsulated antibiotic was tested. Encapsulation of CIPRO apparently increased the amount of antibiotic resident in the vicinity of bacteria in aqueous solution at neutral pH.

Electrophoretic mobility measurements showed that P. aeruginosa cells were negatively charged. The zeta potential of P. aeruginosa was -11.4 ± 2.9 m V in …

Lysine Effect On Ruthenium Red And Alcian Blue Preservation And Staining Of The Staphylococcal Glycocalyx, Theresa A. Fassel, James R. Sanger, Charles E. Edmiston

Cells and Materials

The effect of lysine on ruthenium red (RR) and alcian blue (AB) preservation arid/or staining for transmission electron microscopy of glycocalyces was evaluated for three species of the gram-positive, coagulase-negative staphylococci. A RR and an AB procedure were compared with and without lysine included in the glutaraldehyde prefixation. Minimal or no glycocalyx was preserved or stained by glutaraldehyde fixation only. For all species, the inclusion of lysine increased visualization of fibrous material. RR treatment without lysine, results in sparse or limited fibrous material or artifactual condensations which contrasts with enhanced fibrous material seen when lysine is included with RR. The …

Are Long Term Cryopreservation And Patency Of Vein Allograft Truly Achievable?, G. Pasquinelli, G. L. Faggioli, P. Preda, M. Vici, G. N. Martinelli, R. Giardino, M. D'Addato, J. J. Ricotta

Cells and Materials

Despite extensive experimental work, neither the effect of long term cryopreservation on vein graft architecture nor the failure of alloveins due to graft rejection have yet been investigated. Herein, we investigated ultrastructurally: a) the integrity of rabbit jugular veins following 1, 2 and 3 months of cryopreservation; b) the outcome of the three-month cryopreserved vein auto- and allografts after 1 month of implantation in the rabbit carotid artery; and c) the immunologic response to cryopreserved vein allografts with and without seeded autologous endothelium. Prior to implantation, the cryopreserved rabbit veins were well-maintained except for endothelial cell damage. Following implantation, the …

Influence Of Crystal Structure On The Establishment Of The Bone-Calcium Phosphate Interface In Vitro, J. D. De Bruijn, C. P. A. T. Klein, K. De Groot, C. A. Van Blitterswijk

Cells and Materials

An in vitro rat bone marrow cell system was used to examine the interfacial ultrastructure established between various calcium phosphates and mineralized tissue. The investigated calcium phosphates comprised hydroxyapatite (HA), fluorapatite (FA), tricalcium phosphate (TCP), tetracalcium phosphate (TECP) and magnesium whitlockite (MWL). Both scanning and transmission electron microscopy were used to examine the elaborated interface. The time in which a mineralized extracellular matrix was formed on the various materials differed from 2 weeks on HA, TCP and TECP, to 8 weeks on FA. It was only occasionally observed in some areas on MWL, which might have been due to aluminum …

Degradation Of Polymeric Biomaterials, Shalaby W. Shalaby, Russell A. Johnson, Meng Deng

Cells and Materials

Environmental and processing factors affecting the biostability of medical devices made from traditionally "stable" polymers, such as isotactic polypropylene (PP) and ultrahigh molecular weight polyethylene (UHMW-PE) , were analyzed and their undesirable degradation was related to performance of typical medical devices. Among the critical phenomena determining the biological performance of UHMW-PE and PP devices are oxidation during melt-processing and the propensity of the polymer chains to radiolyse and radio-oxidize. Polyesters and their biomedical devices , which can be designed to degrade predictably, are addressed with some focus on the less obvious determinants of performance.

Outline For Tractor Testing Farm Machinery Museum, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

General statement for developing a museum, justification, current groups, building considerations, and tractor test museum committee

Tractors Acquired For A Museum, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Report mentioning major developments illustracted on tractor acquired for a museum.

Osteoclastic Resorption Of Calcium Phosphate Ceramic Thin Films, J. E. Davies, G. Shapiro, B. F. Lowenberg

Cells and Materials

Sub-micron calcium phosphate ceramic thin films were formed by vertically dipping transparent quartz plates in a particulate sol-gel suspension. Primary adult rat bone marrow cell populations were cultured on the ceramic thin films in conditions known to allow the differentiation of cells of the osteoclast lineage. Monitoring the cultures for periods of 11 to 28 days revealed the creation of resorption lacunae in the thin films by multinucleate cells. Some cultures were heated at 42 °C overnight to remove adherent cells; using bright field light microscopy (LM), after staining with silver nitrate, the degree of resorption could be easily assessed. …

Preferential Adhesion Of Urethral Bacteria From A Mixed Population To A Urinary Catheter, Gregor Reid, Christina Tieszer

Cells and Materials

The ability of uropathogens to adhere to catheters and subsequently colonize the urinary mucosa leads to urinary tract infections which afflict a large patient population. In vitro studies were carried out whereby Escherichia coli Hu734 (water contact angle 12 °) and Enterococcus faecalis (19°) were found to be highly adhesive to silicone latex urinary catheters. The addition of one of four Lactobacillus sp., with water contact angles ranging from 19-105 °, to the suspending fluid caused a 60-86% reduction in pathogen adhesion with a significant effect against E. coli, the organism most commonly found to infect the urinary tract. …

Irrigation Methods For Drainage Reduction Subsurface Drip Vs. Furrow Irrigation, J.. D. Oster, R. B. Smith, C. Phene, A. Fulton, S. W. Styles, T. Fernandes

BioResource and Agricultural Engineering

No abstract provided.

In-Vivo Reactions In Some Bioactive Glasses And Glass-Ceramics Granules, A. M. Gatti, T. Yamamuro, L. L. Hench, O. H. Andersson

Cells and Materials

Two different bioactive glasses and one glass-ceramic were implanted as granules for 2 months in rabbit muscle and for 5 months in sheep jaw in order to study the influence of the biological surroundings on the reactions of the materials.

Scanning electron microscope and energy dispersive X-ray microanalysis showed that a calcium and phosphorous-rich (CaP) surface layer (adjacent to a silicon rich-layer) forms on both glasses in both implantation sites. The glass-ceramic developed only a CaP layer. A chemical process of degradation was more evident in muscle, even though the implantation time was shorter than that in bone. For all …

The Structure Of Urinary Catheter Encrusting Bacterial Biofilms, D. J. Stickler, J. King, J. Nettleton, C. Winters

Cells and Materials

A major complication of long-term urethral catheterization is catheter blockage by encrustation. We have examined 20 encrusted catheters and in each case crystal formation was associated with the presence of bacterial biofilms on the luminal surfaces. Scanning electron microscopy and X-ray microanalysis indicated the presence of struvite and hydroxyapatite in the biofilms. Urease producing bacteria were colonizing 16 of the catheters. Proteus mirabilis was the commonest species being recovered from ten of the catheters. These results support the hypothesis that catheter encrustation has a similar etiology to that of infection-induced urinary stones and confirm that the important target for any …

Mineralization Of An Axially Aligned Collagenous Matrix: A Morphological Study, D. L. Christiansen, F. H. Silver

Cells and Materials

Bone can be described as a highly ordered composite of type I collagen integrated with an inorganic mineral phase. In vitro models of bone mineralization using collagenous substrates have been reported in the literature. This study reports an in vitro system of mineralized reconstituted collagen fibers, with aligned fibrillar substructure. The collagen fibers were mineralized in a double diffusion chamber saturated with respect to calcium and phosphate. The morphology and ultrastructure of the mineral precipitate were evaluated as a function of the pH of the incubating media. Brushite crystal was observed at acidic pH. Large rectangular crystals formed at pH …

Morphological Characterization Of Maltodextrin Derivatives Using Scanning Electron Microscopy, K. K. Singh, D. J. Robison, Y. V. Pathak

Cells and Materials

This paper deals with the study of the significance of the morphological characteristics of some maltodextrin derivatives in the preparation of tablet dosage forms. Six maltodextrin derivatives, M-040, 100, 150, 180, 500, and 700, with varying dextrose equivalent (DE) values and varying degrees of agglomeration were studied for their suitability in the preparation of the tablets based on the morphological characteristics observed by scanning electron microscopy. A comparison of micromeritic properties, moisture absorption, and morphological characteristics of various maltodextrin derivatives is reported.

Immunocytochemical And Lectin-Gold Characterization Of The Interface Between Alveolar Bone And Implanted Hydroxyapatite In The Rat, H. Kawaguchi, M. D. Mckee, H. Okamoto, A. Nanci

Cells and Materials

The tissue response to implanted hydroxyapatite (HAP) in rat alveolar bone was investigated using morphological and cytochemical approaches. High-resolution immunogold labeling was used to examine the distribution of two non-collagenous bone proteins, osteopontin and osteocalcin, and two plasma proteins, a2HSglycoprotein (fetuin) and albumin. Glycoconjugates were characterized by lectin-gold cytochemistry using Ricinus communis I agglutinin and Wheat germ agglutinin. Transmission electron microscopy demonstrated the presence of an electron-dense, lamina limitans-like layer at the HAP particle-bone interface and organic material within the micropores of the particles. Mineral was observed in relation to both these sites. The HAP particle-bone interface was strongly …

A Complexity Analysis Of Smart Pixel Switching Nodes For Photonic Extended Generalized Shuffle Switching Networks, Thomas J. Cloonan, Gaylord W. Richards, Anthony L. Lentine, Frederick B. Mccormick, Harvard Scott Hinton, Stephen J. Hinterlong

Electrical and Computer Engineering Faculty Publications

This paper studies the architectural tradeoffs found in the use of smart pixels for nodes within photonic switching interconnection networks are discussed. The particular networks of interest within the analysis are strictly nonblocking extended generalized shuffle (EGS) networks. Several performance metrics are defined for the analysis, and the effect of node size on these metrics is studied. Optimum node sizes are defined for each of the performance metrics and system-level limitations are identified.

Soil Sampling Made Easier, Mike Bolland, Mike Baker

Journal of the Department of Agriculture, Western Australia, Series 4

A new rotary blade soil sampler has taken the hard work out of collecting soil samples from Western Australia's hard-setting soils to test for soil phosphorus levels .

Conceived and developed by Department of Agriculture technical officer Mike Baker, it should enable soil testing to be more widely adopted. Fortunately, the soil calibration tests that were developed using pogo samples can also be used for the new sampler.

Test 1667: John Deere 7700 Powershift Diesel 19-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

The Anatomy Of Programming Languages, Alice E. Fischer, Frances S. Grodzinsky

Electrical & Computer Engineering and Computer Science Book Series

The specific goals of this book are to help students learn: *To reason clearly about programming languages. *To develop principles of communication so that we can evaluate the wisdom and utility of the decisions made in the process of language design. *To break down language into its major components, and each component in to small pieces so that we can focus on competing alternatives. *To define a consistent and general set of terms for the components out of which programming languages are built, and the concepts on which they are based. * To use these terms to describe existing languages, …

Process Equipment Cost, Biotechnology And Pharmaceutical, Donald S. Remer, Javier H. Idrovo '89

All HMC Faculty Publications and Research

No abstract provided.

Repointing Mortars For Conservation Of A Historic Stone Building In Trinity College, Dublin, Aidan Duffy, Tim P. Cooper, Simon H. Perry

Articles

With atmospheric pollution causing building stone to decay at accelerated rates, conservation of historic stone monuments is becoming an increasingly important issue. Mortar joints have a marked effect on how moisture moves in a wall and, hence, on how the wall weathers. Not only does mortar bind stones together, but also a good mortar will prevent the ingress of moisture (and pollutants), enable the buildings to dry out, accommodate movement and will not act as a source of harmful chemicals capable of attacking the surrounding stone. Thus, poor mortar can have deleterious effects on the stonework. This paper, which is …

Doctor Of Education Specialization In Computing And Information Technology, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Structural Behavior Of Architectural Laminated Glass, R. A. Belir, Joseph E. Minor, H. S. Norville

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Experimental and theoretical investigations conducted over a 20-year time period by several investigators provide sufficient data and information to define, for practical engineering purposes, the behavior of architectural laminated glass under lateral pressures. Investigations included definitions of material properties, theoretical stress analyses, experimental stress analyses, and destructive tests involving monolithic, laminated, and "layered" glass plates of several geometries. The preponderance of data and information indicate that: (1) Architectural laminated glass behaves in a manner similar to monolithic glass of the same nominal thickness under short-term lateral pressures (representative of wind loads) at and below room temperature; (2) the temperature at …

Graduate Catalog Center For Computer And Information Sciences 1993-1994 Catalog, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Multiple Quantum-Well Technology Takes Seed, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

Progress in the development of self-electrooptic-effect devices (SEEDs) is discussed. The devices include the resistor-SEED (R-SEED) device, which can be viewed as a simple NOR gate. The symmetric SEED (S-SEED) and the logic-SEED (L-SEED) devices with improved features, functionality, and performance are also considered. The integration of FETs with multiple quantum well (MQW) modulators (FET-SEED), enables optical interconnections of electronic circuits. Where the SEED technology can be used is discussed, and an experimental optical switching fabric made using these devices is described.

Organic Extracellular Matrix Components At The Bone Cell/Substratum Interface, X. Shen, E. Roberts, S. A. F. Peel, J. E. Davies

Cells and Materials

We have recently shown that differentiating bone cells are capable of elaborating, in vitro, a calcified matrix at the interface with several non-biological substrata which is similar to cement lines found in remodelling bone tissue. From previous morphological observations, this matrix appeared free of assembled collagen fibres which indicated that osteogenic cells produce an initial mineralized matrix before overt collagen fibre production. In the work reported herein, we used six antibodies to extracellular matrix components and two conjugates of secondary antibody, fluorescein and colloidal gold, to initiate a preliminary characterization of the organic components at the bone cell substratum …

The Peo/Pbt Copolymer-Mineralized Matrix Interface In Vitro, A. M. Radder, J. E. Davies, H. Leenders, C. A. Van Blitterswijk

Cells and Materials

Previous implantation experiments have investigated the interaction between a series of PEO/PBT copolymers (Polyactive®) and bone tissue, and shown the morphology of bone-bonding with several PEO/PBT ratios. However, the underlying mechanism of bone-bonding remains largely unknown. Therefore, an in-vitro approach was chosen to obtain more information on the events occurring at the PEO/PBT copolymer-bone interface. Rat marrow cells were cultured on two PEO/PBT copolymer proportions: a 60/40 ratio which is known to bond with bone tissue in-vivo and a 30170 ratio which, within one year of implantation, does not bond with bone. Evaluation was performed with light microscopy, scanning, backscatter …

Phenotypic Characterization Of Copper-Resistant Mutants Of Methylosinus Trichosporium Ob3b, M. (Mark) W. Fitch, D. W. Graham, R. G. Arnold, S. K. Agarwal, P. Phelps, G. E. Speitel, G. Georgiou

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Cultures of Methylosinus Trichosporium OB3b Grown in the Presence of Very Low Concentrations of Copper Synthesize a Soluble Methane Monooxygenase (SMMO) that Efficiently Catalyzes the Oxidation of Trichloroethylene and Other Organic Pollutants. Recently, We Isolated Five M. Trichosporium OB3b Mutants that Express SMMO Activity When Grown in the Presence of Elevated Copper Concentrations (P. A. Phelps, S. K. Agarwal, G. E. Speitel, Jr., and G. Georgiou, Appl. Environ. Microbiol. 58:3701-3708, 1992). Here We Show that, in Contrast to the Results for the Wild-Type Cells, the Addition of Copper to Mutant Cultures Grown on Methane and Nitrate as the Nitrogen Source …