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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 …

Development Of A Rotation Device For Microvascular Endothelial Cell Seeding, G. Pasquinelli, P. Preda, M. Vici, G. N. Martinelli, A. Freyrie, T. Curti, M. D'Addato

Cells and Materials

A rotation device (RD) specifically designed to achieve sterile endothelial cell (EC) seeding of vascular grafts has been developed. The basic characteristics of the RD include: small dimensions, fully autoclavable components, and perfectly sealed graft holders. These features make it possible to maintain sterility during all the steps of EC seeding. This was documented by negativity of all bacteriological assays performed . Moreover, the RD can simultaneously support three vascular grafts with different lengths (20, 40, and 60 cm) and diameters (4-8 mm). EC seeding is performed in the climatized chamber (37 °C; 5 % C02) with constant rotation (0.1 …

In Vitro Bone Formation Associated With Apatite Coated Polylactide, J. D. De Bruijn, A. Van Sliedregt, A. M. Duivenvoorden, C. A. Van Blitterswijk

Cells and Materials

Bone formation onto poly(L-lactide), which was plasma-spray coated with various quantities of hydroxyapatite (0%, 15%, 36% and 100% coverage), was investigated in an in vitro assay. Rat bone marrow cells were grown on the different coatings and the cellular response and elaborated extracellular matrix was examined at the light and electron microscopical level after 1, 2 , 4 and 8 weeks of culture. Proliferation of cells into multilayers was seen on the 0% , 36% and 100% , but not on the 15 % coatings. Coinciding with this was the sparse formation of extracellular matrix on the latter, and its …

Attraction Of Douglas-Fir Beetle, Spruce Beetle And A Bark Beetle Predator (Coleoptera: Scolytidae And Cleridae) To Enantiomers Of Frontalin, B. S. Lindgren

The Bark Beetles, Fuels, and Fire Bibliography

In three separate experiments, Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, preferred traps baited with either (S)-(-)- or racemic (R,S)-(±)-frontalin over those baited with the (R)-(+)-enantiomer. Spruce beetles, D. rufipennis (Kirby), appeared to be attracted equally to both the (S)-(-)- and (R)-(+)-enantiomers, but low catches and high variance made interpretation of the data tenuous. For both species racemic frontalin was as attractive as the preferred enantiomer alone. The bark beetle predator,Thanasimus undatulus (Say), was attracted preferentially to (S)-(-)-frontalin over (R)-(+)- or (R,S)-(±)-frontalin in a Douglas-fir stand, while both enantiomers were equally attractive in a spruce stand.

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. …

Direct Methods In High Resolution Electron Microscopy, D. Van Dyck, M. Op De Beeck

Scanning Microscopy

New approaches are proposed to retrieve the wavefunction at the object and from this, to retrieve the projected structure of the object. The wavefunction is retrieved by capturing images at a series of closely spaced focus values and to process the whole 3D data. The structure of the object is retrieved using a formalism based on electron channelling.

Morphological Three-Dimensional Analysis, C. Gratin, F. Meyer

Scanning Microscopy

This paper presents the main results of our research on mathematical morphology for three-dimensional images. The first issue is to decide which grid must be used. The face-centred cubic grid and the centred cubic grid seem to be more suitable than the cubic grid in terms of possible rotations. For these two grids we derive the formulae for the basic Minkovski measures. Then we show through several examples that extension from 2D to 3D is straightforward for most transformations. The efficiency of direct 3D processing is illustrated by applications to filtering, overlapping particle separation and grey-scale image segmentation.

An Optical Moiré Technique For The Analysis Of Displacements In Lattice Images, C. J. D. Hetherington, U. Dahmen

Scanning Microscopy

High resolution electron microscopy is a means for imaging not only the local structure at a defect or interface but also the displacement field in the surrounding lattice. However, in general it is difficult or tedious to analyse this field which can extend across the entire micrograph. The optical moiré technique, which is based on interference effects between the experimental lattice image and an artificial reference lattice, allows a rapid and accurate measurement of the displacements. Small violations of translation, rotation or mirror symmetries give rise to large changes in the periodicity or orientation of the moiré pattern.

The spacing …

Effect Of Surface Treatments On Dentin Bonding Shear Strength, James L. Drummond, D. Racean, J. Van Scoyoc, A. Steinberg

Cells and Materials

The purpose of this study was to determine whether four different treatments on wet or dry teeth, on the buccal and occlusal surfaces, affected the shear bond strength. The surface treatments consisted of a dentin conditioner (pH = 4.0), 10% phosphoric acid (pH = 1.6), 2.5 % nitric acid (pH = 1.0), and 2.5 % citric acid (pH = 1.0). One dentin bonding system and one dental composite was used for all of the specimens. The teeth were mounted in acrylic, ground and etched with the appropriate agent for 15 seconds. The dentin adhesive and composite were applied and the …

Changes In Intracellular Ca2+ And Structure In Platelets Contacting Synthetic Substrates, L. M. Waples, O. E. Olorundare, S. L. Goodman, R. M. Albrecht

Cells and Materials

Platelet structural changes such as spreading and cytoskeletal reorganization that occur upon contact with synthetic surfaces have been well documented . Structural changes such as spreading will vary depending on the substrate involved . Although platelet structural changes following adhesion have been recorded , the cellular mechanisms including changes in intracellular calcium flux underlying these platelet responses are less well understood. In this study, video microscopy was used to image platelet adhesion and spreading while simultaneously imaging intracellular free Ca2+ levels in individual Fura-2 loaded human platelets. This was accomplished using fluorescence video microscopy coupled with video enhanced asymmetric illumination …

Effect Of Ionizing Y-Radiation On Thermoluminescence And Electron Spin Rosonance Intensities In Milk Protein Concentrate Powders, J. Kispeter, L. I. Horvath, L. I. Kiss

Food Structure

Milk protein concentrate powder has found a wide application as a food ingredient. We investigated the effects of ionizing ')'-radiation at doses ranging from 2 to 20 kGy on electron spin resonance and thermoluminescence intensities in samples of milk protein concentrate powder with varying protein contents (36-73 %wt), containing addltional Fe++ ions (12-910 ppm) and stored under different conditions.

Electron spin resonance and thermoluminescence intensities increased unambiguously with absorbed -ydose. Added Fe++ ions showed a quenching effect as measured by both methods. Storage conditions affected strongly the decay of electron spin resonance signal intensity . Lineshape analysis of thermoluminescence curves …

Application Of Slow-Scan Charge-Coupled Device (Ccd) Cameras To On-Line Microscope Control, O. L. Krivanek, G. Y. Fan

Scanning Microscopy

Autotuning methods for transmission electron microscopy are reviewed, and a distinction is drawn between predictive and non-predictive methods. The predictive methods make better use of the input data and therefore need fewer images to carry out complete autotuning. They typically require high quality of input data, which can be best provided by cooled slow-scan charge-coupled device (CCD) cameras. Two predictive methods are considered in more detail. These are the tilt-induced image shift (TIS) method of Koster, van der Mast and de Ruijter, and a new automated diffractogram analysis (ADA) method, which is introduced in this paper. The ADA method is …

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 …

Extracellular Matrix Vesicles In Endochondral Bone Development And In Healing After Injury, J. Sela, Z. Schwartz, L. D. Swain, D. Amir, B. D. Boyan

Cells and Materials

Matrix vesicles are fundamental components of initial mineral formation in endochondral and primary ossification. Regulation of their structure and function is multi-faceted and involves genomic and nongenomic pathways. Their function in mineralization may include matrix maturation and conveying cellular signals to the extracellular matrix as well. Intravesicular hydroxyapatite crystal formation is associated with primary mineralization; subsequent crystal formation, particularly at later stages, appears to be mediated by other mechanisms.

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 …

Projection Effect Errors In Biomaterials And Bone Research, K. N. Bachus, R. D. Bloebaum

Cells and Materials

Micoradiography and backscattered electron (BSE) imaging are techniques used to investigate the morphologic, histometric, and mineral content changes at the bone/biomaterials interface. Investigators have shown that the superimposition of multiple tissue layers can cause errors with both the morphologic observations and the histometric measurements of bone. The objective of this study was to document errors in the bone mineral content measurements associated with overlapping tissues.

Using a digital image analysis system, microradiographic and BSE images from canine cortical and cancellous bone were captured and analyzed. The results of this study showed that microradiography had more projection effect errors associated with …

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 …

Apatite - Cholesterol Agglomerates In Human Atherosclerotic Lesions, Sara Sarig, Danielle Hirsch, Reuven Azoury, Teddy A. Weiss, Iony Katz, Howard S. Kruth

Cells and Materials

The purpose of this study was to examine the ultrastructural relationships of cholesterol crystals and apatite deposits in human atherosclerotic lesions. Segments of human aortic atherosclerotic lesions were obtained at autopsy , fixed in glutaraldehyde and dehydrated without using any organic solvents. The aortic segments were coated with carbon and subjected to various scanning electron microscope analyses. These included secondary electron imaging, back scattering of primary electrons, energy dispersive X-ray analysis of selected spots followed by area mapping of calcium and phosphorus , and cathodoluminescence.

The information gathered from scanning of selected areas in the lesions by all the techniques …

Measurement Of Electron-Optical Parameters For High-Resolution Electron Microscopy Image Interpretation, A. F. De Jong, A. J. Koster

Scanning Microscopy

A method is presented to measure various electron-optical parameters needed for high-resolution electron microscopy image interpretation with high accuracy. The method is based on the measurement of a series of beam-tilt induced image displacements. The displacements are calculated via cross-correlation of the images, and subsequently fitted to a third-order polynomal in the beam tilt. From two series of images (using the x and y beam tilt coils), the spherical aberration constant of the microscope can be measured, as well as the current values of defocus, beam tilt and astigmatism. The spherical aberration constant of three Philips microscopes is measured with …

Imaging Deformed Proteins: Characterising The State Fully, W. O. Saxton

Scanning Microscopy

By analysing the positions of individual unit cells in the image of a distorted macromolecular crystal, it is possible to achieve considerably more than is achieved by the correlation averaging or unbending now widely practised. It is possible partly to compensate for individual molecular distortion; and it is possible to identify molecules in equivalent environments (which can be expected to be in equivalent states of strain), selective averaging of which yields images that show how strain is accommodated at the sub-molecular level. The possible presence of surface forces applied to the crystal by its support film complicates the analysis and …

The Watershed Transformation Applied To Image Segmentation, Serge Beucher

Scanning Microscopy

Image segmentation by mathematical morphology is a methodology based upon the notions of watershed and homotopy modification.This paper aims at introducing this methodology through various examples of segmentation in materials sciences, electron microscopy and scene analysis.

First, we defined our basic tool, the watershed transform. We showed that this transformation can be built by implementing a flooding process on a greytone image. This flooding process can be performed by using elementary morphological operations such as geodesic skeleton and reconstruction. Other algorithms are also briefly presented (arrows representation).

Then, the use of this transformation for image segmentation purposes is discussed. The …

Phase Space Methods In Image Formation Theory, Victor Castaño, Gustavo Vásquez-Polo, Ramón Gutiérrez-Castrejón

Scanning Microscopy

A review of the basic mathematical principles and properties of some phase space functions (Wigner and Ambiguity functions) is first presented in a more general mathematical context. Then, we deal in detail with three applications : image formation in optical systems (specifically cascading systems of lenses), image formation in Transmission Electron Microscopy, by taking advantage of some formal similarities with the previous examples and, finally, contrast transfer functions in Electron Microscopy in order to obtain 2-dimensional plots which provide information on the behavior of a transmission electron microscope. Also, the relations of these functions with other mathematical tools utilized in …

Reduced Sugar And Sugar-Free Food Preservation, Georgia C. Lauritzen

All Archived Publications

No abstract provided.

Cultural Diversity & Adaptation: The Archaic, Anasazi, & Navajo Occupation Of The Upper San Juan Basin, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

Recent work in the upper San Juan Basin has more than doubled the number of known, as well as excavated, sites. Without exception, this work has modified and expanded long-held views of the PaleoIndian, Archaic, Anasazi, and Navajo people who inhabited the area. The papers presented in this volume reflect these changes and represent the cutting edge of southwestern archaeology.

Effects Of Seeder Design And Seed Placement On Seedling Size And Cull Rates At Western Forest Nurseries, United States Department Of Agriculture, Forest Service

Forestry

Nursery plots sown with the Summit Precision Seeder and the Oyjord Seeder were compared with plots oversown and hand thinned to desired spacings. We studied 26 seedlots of nine conifer species at five Forest Service, U.S. Department of Agriculture, nurseries. Results varied with nursery, species, and seed characteristics. Thinned plots produced less clumping and fewer gaps between seedlings, but showed little or no difference in seedling size, nor in the number of acceptable seedlings.

A Partial Glossary Of Elk Management Terms, United States Department Of Agriculture, Forest Service

Forestry

This glossary helps define terms that have been misused during forest planning. Terms that were developed from research on the influences of timber sales and roads during the summer months have been used inappropriately when referring to winter range, hunting seasons, and other conditions. The glossary is based on the results of an "Elk Management Terminology Workshop" held at the University of Montana's Lubrecht Experimental Forest on April 3-4, 1990.

Plant Community Diversity After Herbicide Control Of Spotted Knapweed, United States Department Of Agriculture, Forest Service

Herbicides and Pesticides

Herbicides were applied to four west-central Montana sites with light to moderate spotted knapweed (Centaurea maculosa Lam.) infestations. Althought knapweed suppression was high, 2 years after the spraying the communities were not converted to grass monocultures. No large declines in plant diversity were caused by the herbicides, and small depressions were probably transitory. By the third year, diversity had increased.