Life Sciences Commons^™

Fine Structure Of The Inner Enamel In Human Permanent Teeth, T. Kodaka, M. Kuroiwa, M. Abe

Scanning Microscopy

Using SEM after EDTA etching, the mid-coronal inner enamel of human permanent teeth was classified into three regions of the 1st, 2nd, and 3rd zones. The 1st zone showing a highly negative birefringence was the innermost 10 - 15 μm enamel. This zone consisted of arcade and circular initial prisms, and the succeeding arcade prisms only. These initial prisms arising perpendicularly to the dentine surface resembled pseudoprisms because these prisms showed a somewhat centripetal arrangement of crystal lites and indistinct prism boundaries. The succeeding prisms were frequently bent following a faint slit within the prism. The 2nd zone adjacent to …

Scanning Electron Microscopy Of Vascular Corrosion Casts - Technique And Applications: Updated Review, A. Lametschwandtner, U. Lametschwandtner, T. Weiger

Scanning Microscopy

The present paper states very briefly the main steps leading to the technique of scanning electron microscopy (SEM) of vascular corrosion casts. From the terms presently used (injection method, microcorrosion cast, injection replica, vascular corrosion cast, vascular cast) the use of "vascular corrosion cast" for lymphatic and blood vessels is recommended. Specification and pretreatment (kind, volume, dosage of anticoagulants, vasoactive substances and spasmolytica used) of the animals examined are referenced as they are available from the literature. The recommendation is given to pay more attention to these parameters than done so far. The steps necessary for producing reasonable and suitable …

Advanced Sem Techniques To Characterize Coal Minerals, Christopher J. Zygarlicke, Edward N. Steadman

Scanning Microscopy

Research at the University of North Dakota Energy and Environmental Research Center (EERC) has focused on methods to characterize the inorganic components in coals. Because the scanning electron microscope and electron probe microanalysis system (SEM/EPMA) provide both morphologic and chemical information, the SEM/EPMA system is well-suited to the characterization of discrete minerals in coal. Computer-controlled scanning electron microscopy (CCSEM), along with simultaneous automated digital image collection, is one means of gaining more detailed insight into coal mineralogy. Computer-stored images of coal surfaces already analyzed for minerals using CCSEM can be reanalyzed to discern mineral morphologies and coal-to-mineral associations. Limitations may …

Proceedings From The 27th Annual Marschall Italian Cheese Seminar, Various Authors

Cheese Industry Conference

No abstract provided.

Backscattered Electron Imaging And Windowless Energy Dispersive X-Ray Microanalysis: A New Technique For Gallstone Analysis, H. S. Kaufman, K. D. Lillemoe, T. H. Magnuson, P. Frasca, H. A. Pitt

Scanning Microscopy

Scanning electron microscopy with or without conventional energy dispersive x-ray microanalysis is currently used to identify gallstone microstructure and inorganic composition. Organic calcium salts are among many biliary constituents thought to have a role in gallstone nidation and growth. However, current analytical techniques which identify these salts are destructive and compromise gallstone microstructural data. We have developed a new technique for gallstone analysis which provides simultaneous structural and compositional identification of calcium salts within gallstones. Backscattered electron imaging is used to localize calcium within cholesterol at minimum concentrations of 0.01%. Windowless energy dispersive x-ray microanalysis produces elemental spectra of gallstone …

Scanning Electron Microscopic Studies Of The Oral Tissue Responses To Dental Implants, David E. Steflik, Ralph V. Mckinney, Allen L. Sisk, Gregory R. Parr, David L. Koth

Scanning Microscopy

Scanning electron microscopy ( SEM) and its associated technologies have proven invaluable in elucidating the interfacial oral tissue responses to dental implants. Since the dental implant must extend from the mandibular or maxillary jaw, through the oral mucosa, and into the oral cavity, these tissue responses include epithelium, connective tissue and bone. The continual occlusal forces acting upon these tissues reinforce the dynamic character of these tissue responses. Immediately upon implantation, a healing phase begins as a response to the implanted biomaterial. Following this immediate response a longer healing phase occurs, beginning approximately 1 week after implantation, resulting in the …

Ultrastructural Investigations Of The Bone And Fibrous Connective Tissue Interface With Endosteal Dental Implants, David E. Steflik, Ralph V. Mckinney, Allen L. Sisk, David L. Koth, Baldev B. Singh, Gregory R. Parr

Scanning Microscopy

The interface between the tissues of the oral cavity and ceramic and titanium cylindrical endosteal dental implants was investigated with correlated light microscopy, transmission electron microscopy and scanning electron microscopy. This study suggested that mandibular bone can directly interface and form an intimate association with one-stage endosteal dental implants. This potential attachment matrix is composed of a composite of calcified bone, and an osteoid unmineralized matrix in association with an apparent osteogenic connective tissue. Further, results from this study suggested that at a level inferior to the junctional epithelium, and superior to the level of crestal bone, fibrous connective tissue …

Scanning Electron Microscopic Quantitative Study Of Changes With Age In Closing Pattern Of Openings Of Dentinal Tubules On Worn Occlusal Surfaces Of Japanese Permanent Mandibular Incisors, Teruyuki Hojo

Scanning Microscopy

Age-related changes in the closing of dentinal tubules of Japanese permanent mandibular incisors were surveyed using a non-destructive replication technique suitable for SEM analysis at the magnifications of up to X3,000. The areas of openings of dentinal tubules on occlusal surfaces decreased significantly between a 20-39-year age group and a 40+ age group, but the number of the openings tended to decrease. Heavy toothwear on occlusal surfaces of these Japanese permanent incisors was evident even at 27 years of age. A subject or 30 years of age showed surprisingly small number of the opening of dentinal tubules on occlusal surface. …

Kidney Structure Investigations Using Scanning Electron Microscopy Of Corrosion Casts - A State Of The Art Review, H. Ditrich, H. Splechtna

Scanning Microscopy

The corrosion casting technique using acrylic resins in the scanning electron microscope (SEM), was originally developed to investigate renal microvascular structure and is now also successfully used in studies on various other organs. However, in the last two decades nearly 100 papers have been published on the renal vascular anatomy of various taxa of vertebrates or on pathomorphological structures of kidneys, using this technique. Analyzing these works, trends and developments in this field can be summed up as follows: The majority of studies are anatomical works on the vascular system of kidneys from all vertebrate classes. In addition, experimental pathological …

Equations Of Charge Distribution In The Environmental Scanning Electron Microscope (Esem), G. D. Danilatos

Scanning Microscopy

In the environmental scanning electron microscope (ESEM), the electron beam together with various signals emanating from the beam-specimen interaction ionize the gaseous medium in the specimen chamber. A detailed derivation of equations describing the charge density and current flow in the system is presented. It is shown that the various causes of ionization operate over distinct regions, which can be separated out by suitable electrode configuration. The electron probe retains a fraction of electrons with the original charge distribution; this is surrounded by a widespread electron skirt, which, in turn, is surrounded by charge created by the secondary electrons, beyond …

Cryo-Preparation And Planar Magnetron Sputtering For Low Temperature Scanning Electron Microscopy, T. Müller, P. Walther, C. Scheidegger, R. Reichelt, S. Müller, R. Guggenheim

Scanning Microscopy

Cryo-preparation is a reliable technique for the structural investigation of food products in low temperature scanning electron microscopy (SEM). Artifacts, such as, the segregation of water/non-water ingredients, occur during the freezing process by the crystallization of ice; they can be helpful for correct interpretation of visualized details, e.g., the detection of water containing compartments. The size of the segregation structures depends on water concentration and specimen thickness. The condensation of water vapor (ice contamination) is influenced by the specimen temperature and the partial pressure of the water inside the vacuum system. Furthermore, the evaporation (sublimation, etching) of specimen water can …

Gelatin Of Myosin Filament Under High Hydrostatic Pressure, Katsuhiro Yamamoto, Takeo Miura, Tsutomu Yasui

Food Structure

Gelation of myosin filaments under high hydrostatic pressure was investigated. At room temperature myosin filaments in 0.1 M KCl and 20 mM phosphate, pH 6.0, formed gels at 280 MPa and a protein concentration above 2 mg/ml or at 210 MPa and 3 mg/ml. However, no pressure-induced gelation was observed at 140 MPa. The gel strengths of pressure-induced gels were almost proportional to the protein concentration and they were comparable to those of heat-induced gels. The association of myosin filaments and the structural disturbance seemed to coincide with the formation of the gel. The microstructure of the pressure-induced myosin gel …

Surface Diffusion Studies By Analysis Of Cluster Growth Kinetics, Martin Zinke-Allmang

Scanning Microscopy

The approach to thermodynamic equilibrium is the driving force for kinetic processes in adsorbate and thin film structure formation. Macroscopic thermodynamic concepts may be used to predict the rates of nucleation, cluster formation and cluster growth. They involve mass transport concepts usually limited by surface concentration gradients. Time and temperature dependence of nucleation and cluster growth, described in terms of cluster ripening mechanism, therefore reveal information on the microscopic surface diffusion processes, including surface structure and surface energies. Examples of structures studied include, Ga, Sn, and Ge on Si, As terminated Si and GaAs surfaces where the activation energies for …

Scanning Tunneling Microscopy And Spectroscopy Of Plasmid Dna, D. P. Allison, J. R. Thompson, K. Bruce Jacobson, R. J. Warmack, T. L. Ferrell

Scanning Microscopy

We present scanning tunneling microscope (STM) images of uncoated deoxyribonucleic acid (DNA) electrochemically mounted on highly-oriented pyrolytic graphite (HOPG) and imaged in air. Images of linear abnormalities inherent to HOPG surfaces that can be confused with DNA are also presented. Scanning tunneling spectroscopic (STS) images generated by superimposing a small, high frequency ac bias onto the de tunnel bias and recording the ac current signal were taken simultaneously with the topographic images. These spectroscopic images reveal contrast due to local conductivity variations and can be used to differentiate DNA molecules from graphite artifacts.

Calcospherite (Calcification Nodule) Size In The Short Rib Polydactyly Syndromes, Helen E. Gruber, Ralph S. Lachman

Scanning Microscopy

The short rib polydactyly syndromes (SRP) are lethal neonatal skeletal dysplasias with a narrow chest, short limbs, and other abnormalities. Type II (Majewski) short rib polydactyly can be distinguished from the Type I/III (Saldino-Noonan) type on the basis of radiographic and histologic changes. Our previous transmission electron microscopic studies suggested unusual patterns of cartilage calcification in these syndromes. We evaluate calcification in the present study using scanning electron microscopy and quantitative morphometry of calcification regions digested to expose calcospherite nodules (calcification nodules), distinctive morphologic structures which form during cartilage calcification. Mean calcospherite area of the Majewski Type II SRP (3.5 …

The Morphology Of Synovial Lining Of Various Structures In Several Species As Observed With Scanning Electron Microscopy, Peter J. Steinberg, Kees C. Hodde

Scanning Microscopy

Data concerning surface morphology of synovial lining of tendons, tendon sheaths, cruciate ligaments, infra-patellar fat pads and peripatellar synovial ridges in various species (rat, rabbit, dwarf goat, sheep, pig, dog, human) are reported on. Supportive studies with transmission electron microscopy (TEM) and light microscopy were performed.

Three principal morphological appearances of the synovium are evident. On structures with a dense fibrous architecture like tendons, tendon sheaths and cruciate ligaments the intimal cells and processes are mostly slender and may tend to orientation in the length-axis of the structure. On the peri- and infrapatellar adipose tissues two principal 'extremes' are seen: …

The Microvasculature Of The Guinea Pig Ureter. A Scanning Electron Microscopic Investigation, S. Aharinejad, A. Lametschwandtner, W. Höltl, W. Firbas

Scanning Microscopy

In 24 albinotic guinea pigs (Cavia porcellus) the gross vasculature and the microvascular architecture of the ureter were studied by light microscopy of tissue blocks and by scanning electron microscopy of vascular casts. The guinea pig ureter is supplied by the renal artery proximally, by the aorta and the internal iliac artery in its mid-segment, and by the uterine and prostatic as well as by the vesical arteries distally. The main arterial trunks run alongside the ureter before they branch to send perforating arterioles to the muscular coat and the mucosal lining. The draining venules are found on …

Histomorphometric Analysis Of The Rat Proximal Tibial Metaphysis By “Linear Scanning”, R. G. Erben, B. Kohn, W. A. Rambeck, H. Zucker

Scanning Microscopy

Twenty-four female Sprague-Dawley rats (10 weeks old, 200g BW) were either sham-operated (n = 6) or ovariectomized (ovx). Ovx rats were divided into 3 groups (n = 6 each) : ovx; ovx + 1,25(OH) ₂D₃; ovx + l,25(OH)₂D₃ + 1,24,25(OH)₃D₃. The vitamin D metabolites were fed orally starting the day after surgery. After 7 weeks all rats were sacrificed and the proximal tibiae were processed undecalcified for quantitative histomorphometry. Conventional histomorphometric analysis of the distal zone (> 1 mm from the growth cartilage) of the tibial metaphysis revealed a dramatic …

Imaging Single-Stranded Dna, Antigen-Antibody Reaction And Polymerized Langmuir-Blodgett Films With An Atomic Force Microscope, A. L. Weisenhorn, H. E. Gaub, H. G. Hansma, R. L. Sinsheimer, G. L. Kelderman, P. K. Hansma

Scanning Microscopy

The combination of an (AFM) atomic force microscope together with microfabricated cantilevers that have integrated tips opens many possibilities for imaging systems of great importance in biology. We have imaged single-stranded 25mer DNA that was adsorbed on treated mica or that was covalently bound with a crosslinker to a polymerized Langmuir-Blodgett (LB) film, the top monolayer of a bilayer system. At low magnification the AFM shows cracks between solid domains, like in an image taken with a fluorescence microscope. At higher magnification, however, the AFM reveals much finer cracks and at still higher magnification it reveals rows of individual molecules …

Morphological Abnormalities In Vitamin B6 Deficient Tarsometatarsal Chick Cartilage, P. G. Masse, V. E. Colombo, F. Gerber, D. S. Howell, H. Weiser

Scanning Microscopy

The aim of this study was to test the hypothesis that deficiency of vitamin B₆ would produce morphological characteristics of osteochondral lathyrism. To accomplish this goal, morphological characteristics of chick cartilage in which lathyrism was produced by two separate dietary regimens was compared to morphological changes encountered in vitamin B₆ deficiency. Vitamin B₆ deficiency should reduce activity of lysyloxidase needed for producing intermolecular cross-links. The question to be addressed was: would this latter deficiency impair collagen morphological features and secondarily other structures indirectly by reducing collagen molecular assembly? Failure of cross-linking of collagen in the positive controls …

A Low Temperature Vacuum Embedding Procedure For X-Ray Microanalysis Of Biological Specimens At Subcellular Level, Romuald Wroblewski, Joanna Wroblewski, Sven-Olof Wikström, Matti Anniko

Scanning Microscopy

The validity of freeze-drying and low temperature embedding in Lowicryl resins has been investigated in studies of ion distribution in mouse embryological inner ear, rat rib growth plate, liver and submandibular gland. The morphological preservation of the tissues was adequate for the identification of different intracellular compartments and extracellular structures. It was also possible to analyze extracellular fluids in the vestibular part of the developing inner ear. Compared with thin cryosections, Lowicryl sections are easier to produce and are more stable during analysis. Freeze-dried embedded material can be easily reorientated during cutting and adjacent sections can be used for other …

Incorporation And Degradation Of Hydroxyapatite Implants Of Different Surface Roughness And Surface Structure In Bone, C. M. Müller-Mai, C. Voigt, U. Gross

Scanning Microscopy

The interface of dense hydroxyapatite (HA) implants with different surface roughnesses was investigated after implantation into the spongy bone of the distal femur of rabbits by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) following transverse fractures in the interface. Each implant displayed considerable changes in surface morphology caused by leaching (increasing pore diameter), corrosion (particulate disintegration), and active resorption by osteoclasts. Macrophages were involved in "cleaning" the surface via phagocytosis of loose implant particles. Newly formed surface elevations provided adhesion points for fibers and fibrils. Subsequent mineralization of these areas stabilized the interdigitation of surface elevations and extracellular …

Surface Diffusion And Islanding In Semiconductor Heterostructures, H. J. Gossmann, G. J. Fisanick

Scanning Microscopy

Molecular beam epitaxy (MBE) is an important technique for the creation of new, non-equilibrium semiconductor materials and structures exhibiting novel physical phenomena. Surface diffusion plays an important role in the growth of these structures, influencing such fundamental growth processes and constants as islanding, critical thickness and epitaxial temperatures. Two approaches to the general problem of surface diffusion and islanding, using the SiGe system as a prototypical semiconductor heterostructure, are discussed: The time evolution of patterned deposits, and kinetic studies of nucleation and growth. While disordered laminar growth occurs for deposition at 300 K, elevated temperatures lead to Stranski-Krastanow (SK) growth …

From Hela Cell Division To Infectious Diarrhoea, J. Stephen, M. P. Osborne, A. J. Spencer, A. Warley

Scanning Microscopy

Hela 83 cells were grown in suspension both randomly and, synchronously using hydroxyurea which blocks cells at the Gl/8 interface. Cryosections were prepared, freeze-dried and analyzed by X-ray microanalysis. As cells moved into S and through M phases [Na] and [Cl] increased; both returned to normal levels upon re-entering Gl phase. The Na/K ratio was 1:1 in Gl phase. Infection of HeLa 83 cells in Gl phase with vaccinia virus resulted in no change in intracellular [Na].

Infection of neonatal mice with murine rotavirus was localized to villus tip enterocytes and gave rise to diarrhoea which was maximal at 72h …

Reproducible Method For Calibrating The Backscattered Electron Signal For Quantitative Assessment Of Mineral Content In Bone, T. M. Boyce, R. D. Bloebaum, K. N. Bachus, J. G. Skedros

Scanning Microscopy

Backscattered electron (BSE) imaging shows promise for orthopaedic and bone research. BSE images of bone may be captured on-line directly from the scanning electron microscope (SEM), and then analyzed to produce a backscattered electron profile (BSEP), a modified image graylevel histogram which is representative of the mineral content in bone. The goals of this work were 1) develop a reproducible graylevel calibration technique for bone specimens, and 2) determine a conservative time interval during which SEM operating conditions would remain stable.

Calibration standards containing pure aluminum and pure magnesium wires were placed in the SEM with human cancellous bone. Baseline …

The Physical State Of Potassium Ion In The Living Cell, G. N. Ling

Scanning Microscopy

This review summarizes more than 30 years of experimental testing (and confirmation) of a key postulate of the association-induction (AI) hypothesis: most K⁺ ions in resting cells are adsorbed on 𝛃-and 𝛄-carboxyl group of cell proteins in a close-contact one ion-one site manner. Failure of healthy, cytoplasm-free, squid axon-membrane sacs to selectively accumulate K⁺ over Na⁺ and success of muscle cells without a functional cell membrane (and postulated pumps) to achieve the same, point to the cytoplasm as the seat of selective K⁺ accumulation. Four independent techniques unanimously confirmed the predicted localization in striated muscle cells, …

Tumor-Like Growth Of Antlers In Castrated Fallow Deer: An Electron Microscopic Study, Richard J. Goss

Scanning Microscopy

Male deer regenerate new sets of antlers each year. When fully grown, rising levels of testosterone promote antler ossification, cutting off the blood flow and causing the velvet integument to be shed. After the mating season, the old antlers fall off to be replaced by new ones.

When the adult fallow deer is castrated in autumn or winter, its bony antlers are shed and replaced by usually shorter regenerates that remain permanently viable and in velvet. If prevented from winter freezing, these antlers continue to grow thicker each year, eventually giving rise to amorphous outgrowths, or antleromas, from their sides. …

Theory Of Active Transport Across Frog Skin And Other Bifacial Cell Systems: A Subsidiary Of The Association-Induction Hypothesis, Gilbert N. Ling

Scanning Microscopy

This review presents the theory of solute transport across frog skin, epithelial cells of the intestine, the kidney tubules, and other similar systems. This theory is a part of a broader theory of the living cell, called the association-induction hypothesis.

The central pumping mechanism is the cyclic activity of a sponge-like cytoplasmic protein(s), which alternately sop-up (by adsorption) the solute being transported and squeeze it out again (by desorption) into the cytoplasmic water at a high concentration level. The uptake phase begins with the adsorption of ATP on key cardinal sites of the protein involved; the release phase is triggered …

Microstructural Characterization Of Mg-Al Spinel Powders, Fabio Carassiti, Edoardo Proverbio, Gualtiero Gusmano

Scanning Microscopy

Mg-Al spinel powders have been prepared by thermal decomposition of a mixture of: A-aluminium and magnesium nitrates; B-aluminium and magnesium hydroxides; and C-aluminium hydroxide and magnesium oxalate.

The initial and the final powders were both characterized by specific surface area measurements, mercury intrusion porosimetry, X-ray diffraction, and scanning electron microscopy. The results showed that the preparation process sharply influences the final microstructure of the spinel powders. In particular while the shape and particle dimensions of the samples prepared by mixture of aluminium and magnesium nitrates are mainly influenced by crushing process, the preparation via mixed magnesium and aluminium hydroxides precipitation …

Advances In Corrosion Casting Methods, K. C. Hodde, D. A. Steeber, R. M. Albrecht

Scanning Microscopy

This paper briefly discusses the concept of corrosion cast preparation (primarily of blood vessels), the use of the scanning electron microscope (SEM) to study these casts and the observations which can be made, together with the merits and the limitations in various applications. A number of reviews and surveys are quoted in which the different injection media, injection methods, animal preparations and corrosion procedures are described. A new procedure of cleaning the corrosion casts with sodium hydroxide and Triton X-100 is described. The observations which can be made are listed and illustrated both on the cellular level as well as …