Engineering Commons^™

The Articular Cartilage Of The Rabbit Knee: A Scanning Electron Microscopy Study, Daniel Levanon, Haim Stein

Cells and Materials

The surface morphology of eight sectors in the rabbit knee articular cartilage was studied using scanning electron microscopy. Cartilage surfaces showed wide variation in the shape, dimensions , and density of gaps and acellular processes. Patellas and load-bearing condyles revealed a relatively higher density of processes than did load-free condyles. Surface processes and gaps were abundant. They might represent a condensation product(s) of hyaluronic acid/protein complex that accrues during cycles of loading/weight bearing.

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 …

Adhesion And Spreading Of Human Fibroblasts On Superhydrophobic Fep-Teflon, H. J. Busscher, I. Stokroos, J. G. Golverdingen, J. M. Shakenraad

Cells and Materials

Adhesion and spreading of human fibroblasts was studied on hydrophobized and hydrophilized FEPTeflon, and compared with adhesion and spreading on untreated FEP-Teflon and Tissue culture polystyrene (TCPS). Superhydrophobic FEP-Teflon was prepared by ion etching followed by oxygen glow-discharge. Hydrophilic PEP-Teflon was prepared by ion etching only. Water contact angles of the modified surfaces were 140- 1500 and 5-10° for the hydrophobic and the hydrophilic variant, respectively. (Untreated FEP-Teflon: 109°). Spreading of human skin fibroblasts significantly increased on hydrophilic FEP-Teflon (257 μm2 per cell), whereas a significant decrease was observed on superhydrophobic FEP-Teflon (158 μm2 per cell), as compared to untreated …

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 …

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. …

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.

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 …

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 …

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.

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 …

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 …

Drainage Of Sandplain Seeps For Salinity Control And Stock Water Supplies, Richard George, Peter Frantom

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

Sandplain seeps are derived from a shallow groundwater system which flows from the deep sandplain soils upslope. Seeps result in small areas of salinity and waterlogging, which can be the focus of soil erosion. Sandplain seeps may represent as much as 10 per cent of Western Australia's salt problem in the drier agricultural area. Several drainage experiments conducted between 1986 and 1989 determined the best methods of reclaiming sandplain seeps.

This article discusses the results of these drainage experiments. It comments on the most suitable method for reclaiming sandplain seeps and developing them for stock water supplies.

Whole-Farm Planning : Success At Wilgi Creek, Kevin Shanhun

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

Ian and Bev Lynch own Wilgi Creek, a 376 ha mixed farming property at West Mount Barker in the 700 mm rainfall zone. In 1983, they started a whole-farm plan to overcome the problems of declining production caused by waterlogging (their biggest problem), salinity and deterioration of the remnant native vegetation. Today, their property is an example of a successful, wholefarm land conservation plan based on agroforestry, timber production, water harvesting and improved pastures.

Properties Of Ruthenium Oxide Coatings, Roger M. Hawk, Kamesh V. Gadepally, David N. Patangia

Journal of the Arkansas Academy of Science

Ruthenium oxide coatings have been deposited on titanium substrates using a flood coating process. These films were heat treated for varying times and temperatures. The resulting films subsequently were characterized by performing resistivity and SEM analyses. Resistivity of the ruthenium oxide coating was found to be extremely dependent upon the firing temperature. Effect of the process conditions and formulations of the coatings on the morphology with respect to their electrical characteristics is presented. Capacitors were fabricated using plates coated with ruthenium oxide coatings. Capacitance versus heat treatment temperatures are discussed and at one firing temperature (480'C), the capacitance was 50 …

Simple Synchronous Detector For Spectroscopic Studies, Mokhtar Mofidi, M. Keith Hudson, Reagan Cole, James D. Wilson

Journal of the Arkansas Academy of Science

Lock-in-amplifiers are used in many applications for signal processing and offer the ability to discriminate high levels of noise. While these instruments are very powerful and offer many features, they are not portable and are expensive. An economical and easy to use alternative circuit is presented which incorporates pre-amplification, reference, and synchronous detection on one circuit board. The design can be used in laboratory or process control situations where its small size and low cost are advantageous. The circuit was successfully applied to moderate and high level signals as seen in flame infrared emission detection and in a portable radiometer …

Radiometer For The Investigation Of Infrared Emissions From Flames And Rocket Plumes, Kathy Underhill, M. Keith Hudson, Jason Willis, Mokhtar Mofidi, Matthew J. Russo

Journal of the Arkansas Academy of Science

A prototypical radiometer using standard one inch interference filters and a lead selenide detector was constructed for use in flame and rocket plume studies. This radiometer was designed to employ a 600 Hz chopper and chopper frequency/phase reference circuit for signal processing. Bandpass filters centered for either 2.7 mum or 4.45 mum were placed in the optical path. The passed carbon dioxide or water vapor band energy irradiated the lead selenide detector, resulting in an output voltage. This signal was then fed into a dedicated synchronous detector. The signal was then recorded by a computer system equipped with an analog-to-digital …

Homogenous Functions In Thermodynamics, Stephen R. Addison

Journal of the Arkansas Academy of Science

No abstract provided.

Data Acquisition And Control Program For Chromatography, M. Keith Hudson, William G. Hood

Journal of the Arkansas Academy of Science

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Narrow-Winged Seeder Points Reduce Water Erosion And Maintain Crop Yields, Kevin Bligh

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

Sowing crops without loosening the topsoil by tillage reduces water erosion. It can increase infiltration of rainfall into loamy soils, thereby reducing runoff and increasing potential crop yields. Crop yields were maintained after I1 seasons of seeding an Avon Valley loam near Beverley with minimum and no-tillage seeding operations. Infiltration increased significantly from 80 per cent of the 1983 growing-season rainfall under the traditional three tillage operations, to 87per cent under a single tillage operation using a combine seed drill. Infiltration increased further to 96 per cent under a no-tillage system using a triple^lisc drill. At Gnowangerup, 80 per cent …

Technological Upgradation Policies Of The Steel Industry And Impact Of The Steel Industry In The Indian Economy, K K Saxena, Binayak Rath

IIMB Management Review

In India, the iron and steel industry in general occupies an important Position among the manufacturing industries. The priorities attached to this sector can be explained from the Second Five Year Plan document which mentioned that the expansion of iron and steel industry has obviously the highest priority than other industries because the tempo of progress of the economy. Hence, Second Plan onwards the industry has made a rapid stride in our economy. A number of Integrated Steel Plants (ISPs) in the public sector have been set up to boost up production. Today these ISPs contribute a significant portion of …

Linear Programming By G.V. Shenoy, New Delhi: Wiley Eastern Limited, 1989., A K Rao

IIMB Management Review

No abstract provided.

Irish Building Services News

Building Services Engineering

No abstract provided.

Sahkti Limited, Sanjoy Goel

IIMB Management Review

No abstract provided.

Ole Miss Engineer 1990

Ole Miss Engineer

No abstract provided.

Irish Building Services News

Building Services Engineering

No abstract provided.

Perceived Risks Versus Actual Risks: Managing Hazards Through Negotiation, Kristin S. Shrader-Frechette

RISK: Health, Safety & Environment (1990-2002)

The author describes what she calls the "Expert-Judgment Strategy", finding that, because it discounts lay perceptions of Risk, it interferes with the acceptance of important but Risky technologies.

Irish Building Services News

Building Services Engineering

No abstract provided.

The Role Of Scientists In Risk Assessment, Halina Szejwald Brown, Robert L. Goble

RISK: Health, Safety & Environment (1990-2002)

The authors argue that Risk assessors belong to a profession and offer an alternative to the 1983 National Research Council model defining Risk assessment. They support and illustrate their model by reexamining three familiar Risk assessments: ethylene dibromide, WASH 1400, and Ice Minus Bacteria.