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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

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 …

A Comparative Study Of Bovine Pericardium Mineralization: A Basic And Practical Approach, Branko B. Tomazic, Chakwan Siew, Walter E. Brown

Cells and Materials

The biomineralization of bovine pericardium (BP) heart valve bioprostheses was investigated by simulation of the process under in vitro and in vivo conditions. The nature and composition of calcific deposits that formed in human heart valve bioprostheses were compared with the mineral formed on BP discs immersed in a calcifying medium or subcutaneously implanted into Sprague-Dawley rats. The early stage of experimental biomineralization in vitro took place on the surface only, while in vivo deposition appeared to be intrinsic, as documented by histological cross sections. The chemical composition of the initial mineral phase formed under in vitro conditions had a …

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 …

Natural Systems For Preventing Contamination And Growth Of Microorganisms In Foods, King-Thom Chung, Chris A. Murdock

Food Structure

Food-borne illness is a vast and costly worldwide problem. Although complex, it may be divided into two major types of animal and human disease: intoxication caused by toxic substances in food and secondly, infection, caused by microorganisms. Toxic substances may be already present in foods, or they may be produced by microorganisms through contamination and proliferation in food. Prevention of the invasion of foods by microorganisms may be achieved by effective use of intrinsic factors found in plants and animals. These factors include pH, moisture content, oxidationreduction potential, nutrient content, biological structures, and antimicrobial constituents. A second type of natural …

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. …

Lecture 16: What I Was Hired To Do Is Not Part Of My Job, James A. Macmahon

Last Lectures

No abstract provided.

Strategies For Improving The Cytochemical And Immunocytochemical Sensitivity Of Ultrastructurally Well-Preserved, Resin Embedded Biological Tissue For Light And Electron Microscopy, Jan A. Hobot, Geoffrey R. Newman

Scanning Microscopy

Many techniques for processing tissue into resin are available, varying from conventional room temperature to low temperature procedures. The problem is to choose an appropriate method to suit the biological specimen under study. Room temperature approaches with aldehyde and osmium fixation do not give optimal retention of immunoreactivity. Osmium can be removed from sections, but recovery of immunosensitivity is reduced. Osmium post-fixation can be omitted, but heat polymerization of resins causes tissue extraction and loss of immunoreactivity. Alternative techniques rely on the use of milder polymerization methods and avoid osmium. However, while providing an improvement, this alone is not sufficient …

High Voltage Electron Microscopy And Low Voltage Scanning Electron Microscopy Of Human Neoplastic Cell Culture, Marek Malecki

Scanning Microscopy

Improved procedures were developed to correlate cell culture data with the images provided by advanced ultrastructural technologies. These procedures were compatible with the two main types of cellular behavior: adherent, spreading (melanomas, rhabdomyosarcomas) and non-adherent in suspension (leukemias).

The ultrastructure and function of spreading neoplastic cells primarily depend on surface properties of the attaching substrates. Therefore, the films used for cultured cell whole-mount ultrastructural analysis must have adherence features identical to those of standard cell culture vessels. Improved procedures were developed to produce the polystyrene films of required qualities. These films allowed processing of cells for electron microscopy including chemical …

Adsorption Staining Of Freeze-Substituted And Low Temperature Embedded Frog Skeletal Muscle With Cesium: A New Method For The Investigation Of Protein-Ion Interactions, L. Edelmann

Scanning Microscopy

A new adsorption staining method for transmission electron microscopy is described by means of which cellular adsorption sites of alkali-metal ions can be visualized in freeze-substituted and low temperature embedded biological material. The main features of this staining method are: 1) the use of Cs⁺ -ions which are known to accumulate in living cells like K⁺ -ions and 2) the removal of the staining solution from thin sections of the embedded material by centrifugal force. It is shown that sections of freeze-substituted and Lowicryl embedded frog skeletal muscle which has not been treated with chemical fixatives can be …

Restoration And Expansion Of Bear River Migratory Bird Refuge, Brigham City, Utah, Environmental Assessment, U.S. Fish And Wildlife Service

Environmental Assessments (UT)

This Environmental Assessment is designed to evaluate possible actions for preserving and managing the wetland habitat on Bear River Migratory Bird Refuge (Refuge) and to consider additional wetlands for protection of environmental, wildlife, and recreational values.

Preservation And Immunogold Localization Of Lipids By Freeze-Substitution And Low Temperature Embedding, Wim Voorhout, Ida Van Genderen, Gerrit Van Meer, Hans Geuze

Scanning Microscopy

The success of postembedding immunocytochemistry depends largely on the preparation methods. The requirements for structural preservation and immunocytochemistry are in some cases contradictory. This is especially the case in the study of lipid-rich structures and the localization of lipid components. Earlier work on freeze-substitution has shown that this method is very promising for the preservation of lipids and the immunocytochemical localization of lipids at the electron microscopical level.

In this study we show that freeze-substitution in combination with low temperature embedding in Lowicryl HM20 has fulfilled this promise. Lamellar bodies in alveolar type II cells contain about 90% lipids and …

Diffusion Of Water In Biological Tissues, H. E. Rorschach, C. Lin, C. F. Hazlewood

Scanning Microscopy

A method is presented for obtaining simple approximate solutions for the problem of self-diffusion in an ordered array of obstacles. Our results are compared with some previous exact and approximate solutions, and we find that our method agrees well with the exact results over a large range of the volume fraction of the obstructions. It is shown that there is an important distinction between measurements of the diffusion coefficient by the capillary flow method and the spin-echo method. The modifications for the spin-echo case are given and applied to recent measurements on the anisotropy of the self-diffusion of water in …

Reliability Of Intracellular Water And Ion Distributions As Measured By X-Ray Microanalysis - A Review, Thomas Von Zglinicki

Scanning Microscopy

X-ray microanalysis can be an important tool to reveal the spatial relationships between polyelectrolytes, ions, and water as they occur within cells and tissues in vivo. To reach this goal, at least two of these three closely interrelated variables should be measured independently. Moreover, the absence of systematic errors should be proven.

The present review discusses the probability of artificial ion and water shifts between intracellular compartments due to the growth of dendritic ice crystals much larger than the cross-sectioned remnants commonly seen in frozen-dried sections. Considering the possible mechanism of ice crystal growth it is concluded that ions and …

Cryopreparation Of Tissue For Clinical Applications Of X-Ray Microanalysis, Godfried M. Roomans

Scanning Microscopy

A number of diseases is associated with changes in ion and/or water distribution at the tissue or cell level, and X-ray microanalysis can be used to investigate the relationship between the disease process and the changes in elemental distribution. For analysis of diffusible elements by X-ray microanalysis, the tissue has to be prepared by cryotechniques. To carry out studies of this kind in a clinical environment poses a number of problems. Some of these problems occur already before the tissue is frozen, others are caused by the practical and ethical limitations that are imposed on the freezing method itself when …

Distributive Effects Of Forest Service Attempts To Maintain Community Stability, Steven E. Daniels, William F. Hyde, David N. Wear

Sociology, Social Work and Anthropology Faculty Publications

Community stability is an objective of USDA Forest Service timber sales. This paper examines that objective, and the success the Forest Service can have in attaining it, through its intended maintenance of a constant volume timber harvest schedule. We apply a three-factor, two-sector modified general equilibrium model with empirical evidence from the timber-based counties of western Montana. Departure from a market responsive timber policy can have positive impacts on the wood products sector, but the net effects on the local community are very small. The costs to the public treasury of pursuing such a policy dwarf these small community benefits.

Rainbow Bridge National Monument General Management Plan, Development Concept Plan, Resource Management Plan, Interpretive Prospectus, And Environmental Assessment, United States, Department Of The Interior, National Park Service

Resource Management Plans (UT)

This General Management Plan provides the National Park Service with direction for long-range management, development, and use of the Rainbow Bridge National Monument. The plan responds to new issues identified during the planning process when the draft plan was published in September of 1990. A main concern expressed during public review of the draft plan was diverse public expectations for visitor experience, crowding, and the high number of visitors accessing a limited area of Rainbow Bridge. In addition, the plan and environmental assessment address these diverse public expectations along with the issues of a visitor experience, protection of natural and …

Ab Initio Study Of Intermolecular Potential Of H2o Trimer, G. Chalasinski, M. M. Szczesniak, P. Cieplak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Nonadditive contribution to the interaction energy in water trimer is analyzed in terms of Heitler–London exchange, SCF deformation, induction and dispersion nonadditivities. Nonadditivity originates mainly from the SCF deformation effect which is due to electric polarization. However, polarization does not serve as a universal mechanism for nonadditivity in water. In the double‐donor configuration, for example, the Heitler–London exchange contribution is the most important and polarization yields the wrong sign. Correlation effects do not contribute significantly to the nonadditivity. A detailed analysis of the pair potential is also provided. The present two‐body potential and its components are compared to the existing …

Comparison Of The Effects Of Three Different Grinding Procedures On The Microstructure Of "Old-Fashioned" Non-Stabilized Peanut Butter, Clyde T. Young, William E. Schadel

Food Structure

Three different grinding procedures were utilized to prepare "old-fashioned" non-stabilized peanut butters. A leading commercial brand of stabilized peanut butter was used for comparison. The microstructure of each non-stabilized peanut butter was then evaluated with light microscopy and compared to the microstructure of the commercial brand of stabilized peanut butter. Major findings include: (1) dense spatial relationships of protein bodies, starch grains, and cell and tissue fragments that exist in "old-fashioned " non-stabilized peanut butter as compared to the well-dispersed spatial relationships which exist in commercially prepared stabilized peanut butter; and (2) degree of homogenization in the nonstabilized peanut butters …

Practical Methods For Identification Of Rice Endosperm Protein Bodies And Fecal Protein Particles In Light Microscopy, D. L. Barber, J. N. A. Lott, D. A. Harris

Food Structure

Indigestible 1-3 ~m protein 'cores', particles that originate from protein bodies of rice endosperm, were examined in bright-field and fluorescence microscopy, using a variety of histological and histochemical procedures. Our application of histological, histochemical and chemical approaches to a study of the feces of aoimals fed rice-containing diets has resulted in the development of methods for routine identification of insoluble rice fecal protein particles. For the specific identification of rice endosperm storage protein, whether protein bodies, cores or fecal protein particles, aqueous eosin Y stain in conjunction with fluorescence microscopy, and a combination of orange G + aniline blue in …

Textural And Microstructural Properties Of Frozen Fish Mince As Affected By The Addition Of Nonfish Proteins And Sorbitol, K. S. Yoon, C. M. Lee, L. A. Hufnagel

Food Structure

Changes in textural and microstructural properties of washed and unwashed frozen fish mince were studied as affected by the addition of non fish proteins (soy protein isolate, milk protein isolate, egg white, and wheat gluten at 2 , 4 or 6%) and 6% crystalline sorbitol. Soy and milk proteins and sorbitol reduced the hardness of frozen fish mince, while egg white and wheat gluten made the texture firmer without rubberiness developing after frozen storage. All nonfish proteins and sorbitol stabilized the myofibrillar organization by reducing freeze-induced contraction of myofibrils.

The mechanisms of reducing texture hardening appear to be different between …

Scanning Electron Microscope Observations Of Growth And Ochratoxin - A Production Of Aspergillus Alutaceus Variety Alutaceus (Formerly A. Ochraceus) On Gamma-Irradiated Barley, J. G. Szekely, W. S. Chelack, S. Delaney, R. R. Marquardt, A. A. Frohlich

Food Structure

Scanning electron microscope examination, colony counting and biochemical studies were conducted to describe the effect of gammairradiation on growth and ochratoxin A production by Aspergillus alutaceus. Irradiation at a dose of 1.0 or 2.0 kGy reduced the level of mold growth greatly relative to unirradiated controls. Growth in the irradiated samples after 7 to 12 day incubation was mainly in cracks in the hull, and less mycelium was seen on the grain surface. In unirradiated controls, mycelial growth was heavy and, although conidial heads were most abundant in cracks in the hull, they were seen over the whole surface. Vhen …

Microstructural Studies Of Gluten And A Hypothesis On Dough Formation, T. Amend, H.-D. Belitz

Food Structure

The transformation of a mixture of water and wheat flour into a viscoelastic dough was studied by light microscopy, scanning and transmission electron mi croscopy. In flour particles, gluten protein fills up the space between the starch granules forming a three- dimensional network. Dough formation is the result of the adhesion of the protein networks of individual flour particles to one another and their extension during kneading. In the course of the kneading process protein films form from the strands by bidirectional extension. The strands of the gluten network consist of randomly arranged protein threads which are twisted to form …

Project Reports, Various Authors

Other Documents

No abstract provided.

Scanning Electron Microscopy Studies Of The Prevention Of Bioprosthetic Heart Valve Calcification With Controlled Release Polymeric Matrices, Yashwant V. Pathak, James Boyd, Thomas P. Johnston, Judith T. Levy, Gershon Golomb, Frederick J. Schoen, Robert J. Levy

Cells and Materials

Pathologic calcification is the principal failure mode of bioprosthetic heart valves fabricated from glutaraldehyde pretreated porcine aortic valves. Bovine pericardial bioprosthetic valves also fail frequently by calcification. This review covers the novel uses of the scanning electron microscope (SEM) for investigating the pathology and prevention of bioprosthetic heart valve calcification. The progression and growth of calcific lesions in the bioprosthetic heart valve tissues has been documented using SEM with elemental localization by energy dispersive X-ray analysis (EDX). Controlled release polymeric matrices consisting of either ethanehydroxydiphosphonate, FeC13 or Al(N0₃) 3 coimplanted with bioprosthetic tissue prevent experimental bioprosthetic calcification. SEM …

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 …