Biology Commons^™

A Straightforward Scanning Electron Microscopy Technique For Examining Non-Metal Coated Dental Hard Tissues, S. M. Mccormack, F. J. Tormo, J. D. B. Featherstone

Scanning Microscopy

Modifications to the standard operating settings for accelerating voltage , condenser lens current, scan rate, working distance and tilt on the conventional scanning electron microscope (SEM) enabled non-metal coated dental hard tissues and synthetic apatite pellets to be viewed free of charging effects . Well -resolved images at magnifications as high as 35,000x were achieved using accelerating voltages less than 5 kV . The methodology detailed here allowed for serial SEM examination of the same sample at various points during an experimental procedure , and may be applied to other sample types. The procedure is non-destructive to the sample and …

Microcirculatory Pathways And Blood Flow In Spleen: New Insights From Washout Kinetics, Corrosion Casts, And Quantitative Intravital Videomicroscopy, A. C. Groom, E. E. Schmidt, I. C. Macdonald

Scanning Microscopy

The dynamics of splenic microcirculatory blood flow and the role of the spleen with respect to red blood cells (RBCs) have been elucidated by means of several different experimental approaches. First, the organ was treated as a 'black box' and input/output relationships were studied, such as the kinetics of RBC and plasma washout during Ringer perfusion. Second, micro-corrosion casts were prepared from minimal amounts of injected material, such that 'fast' pathways for flow were selectively identified. Third, high-resolution video-microscopy was carried out in rat and mouse spleens transilluminated in vivo, with subsequent quantitative analysis of the data. New insights were …

Microprobe Analyses Of The Potassium-Calcium Distribution Relationship In Predentine, H. J. Höhling, H. Mishima, Y. Kozawa, T. Daimon, R. H. Barckhaus, K. -D. Richter

Scanning Microscopy

Apex regions of continuously growing incisors of Wistar rats were quickly dissected, shock-frozen in liquid nitrogen-cooled propane, freeze-dried at -80 °C and infiltrated with Spurr's resin . 400nm thick dry sections were cut with a diamond knife on an ultramicrotome . Relatively flat sections were transferred with an eye lash onto collodium coated aluminum grids. They were flattened with a glass stick and by placing another collodi um coated aluminum grid just on top of the first one, exerting a uniform pressure . After carbon coating the sections were observed using the backscattered and secondary electron signals in a scanning …

The Hall Method In The Quantitative X-Ray Microanalysis Of Biological Specimens: A Review, Godfried M. Roomans

Scanning Microscopy

In the two decades since its inception by T.A. Hall, the continuum theory of quantification has become the general method for quantitative analysis of biological specimens. Although the method was originally developed for thin specimens, its use has been extended to thicker specimens, and it has also been used in quantitative determinations of local water content. The single most important difficulty in the application of the "Hall method" is the accurate calculation of the extraneous continuum, i.e., the continuum due to non-specimen sources. The different variations in methods for quantitative analysis of local water content are critically compared and a …

High Energy Proton Induced X-Ray Emission And Its Applications, J. S. C. Mckee, G. R. Smith, A. A. Mirzai, M. S. Mathur, N. M. Halden, C. Pinsky, R. Bose

Scanning Microscopy

High energy protons of energies between 30 and 60 MeV are particularly valuable in particle induced X-ray analysis of elements in the rare earth region and above. Transmission samples of thickness up to 100 μm can be used, and damage to both biological and mineral samples is minimal. Detection limits are estimated, and the use of Fourier transformation techniques in the analysis of data is discussed in some detail. The quality of the raw data from mineralogical and biological experiments is such as to permit immediate identification of all elements above Germanium present at the part per million level or …

Digital Correlation Of Ion And Optical Microscopic Images: Application To The Study Of Thyroglobulin Chemical Modification, J. C. Olivo, E. Kahn, S. Halpern, P. Fragu

Scanning Microscopy

A method has been developed in order to digitally correlate ion and optical microscopic images of the same sample areas. Serial cross-sections of human thyroid tissue were analyzed by secondary ion mass microscopy and by light microscopy. The resulting chemical and immunochemical map images were superimposed and correlated by means of a two-pass registration algorithm which allows to correct for geometrical distortions introduced by the ion microscope. Results are presented for the study of thyroglobulin chemical modification in pathological thyroid tissue that demonstrates heterogeneous molecular activity.

Direct Observations Of Surface Diffusion, Gert Ehrlich

Scanning Microscopy

The field ion microscope, with its ability to depict individual metal atoms on crystals, has made it possible to measure diffusivities of individual atoms. After a brief sketch of the technical problems in such quantitative studies of surface diffusion, data on the effects of different surface structures upon the diffusion characteristics of individual a toms are presented for both bee and fee metals. Through the use of the field ion microscope the mechanisms of atomic motion have for the first time become accessible to direct examination; recent studies are presented which indicate that the traditional view of surface diffusion as …

Characteristics Of Granulation Tissue Which Promote Hypertrophic Scarring, C. Ward Kischer, Jana Pindur, Peggy Krasovitch, Eric Kischer

Scanning Microscopy

Hyper trophic scars and keloids are characterized by nodules of collagen that originate in granulation tissue arising from full thickness or deep 2° injuries to the skin. Fifty-six granulation tissues of varying ages post-injury were examined morphologically for evidences of how the nodules and, thus, the scar form. New microvessels grow in ascension towards the free surface in a milieu of inflammatory cells and fibroblasts. Collagen deposition increases with time from the base of the wound to the free surface and begins to concentrate between lateral branching of the new microvessels. Computer derived serial reconstructions of hypertrophic scar nodules indicate …

Scanning Electron Microscopy Of The Celloidin-Embedded Inner Ear Sections, Kunihiro Mizuta, Tomoyuki Hoshino, Hirofumi Morita

Scanning Microscopy

The nerve fibers running inside the organ of Corti were studied in cats by scanning electron microscopy (SEM). The fixed temporal bones were decalcified and embedded in celloidin according to the conventional method. Thick serial sections (100-150 μm) were cut parallel to the basilar membrane. After removing the celloidin, the sections were freeze-dried in t-butyl alcohol. Though some outer hair cells had been deformed, the nerve fibers were well preserved for analysis.

Some new findings were observed in the present SEM study. The tunnel spiral bundle in a kitten took an atypical course on the floor of Corti's tunnel apart …

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 …

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 …

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 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 …

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 …

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 …

Approximate Solutions Of The Boltzmann Equation For Secondary Electron Emission: Results And Comparisons To Experiments, A. Dubus, J. Devooght, J. C. Dehaes

Scanning Microscopy

The aim of the present paper is to survey the theoretical work performed in Brussels about secondary electron emission (SEE). Two new approximate solutions of the Boltzmann equation for internal secondary electrons are applied to both electron and ion induced SEE. Using a realistic set of interaction cross sections, most calculated characteristics of electron emission compare fairly well to experiments.

The "improved age-diffusion" model can be used to calculate the electron yield, the energy and angular spectrum and also the depth and radial distributions of outgoing electrons for incident electrons and ions.

The "transport-albedo" model assumes an uniform internal electron …

Multielement Analysis Of Biological Materials By Particle-Induced X-Ray Emission (Pixe), Willy Maenhaut

Scanning Microscopy

An analytical particle-induced X-ray emission (PIXE) procedure for the multielement analysis of biological materials consists of various stages. These include sample and specimen preparation, specimen bombardment, spectral data processing, quantification and correction for matrix effects. Critical aspects of the procedure are contamination and/or losses during sample and specimen preparation and the danger of radiation or heat-induced losses during specimen bombardment. With optimized PIXE procedures precisions of 1-2% and an accuracy of better than 5% are obtainable, whereas the detection limits are down to 0.1 μg/g. Because of its inherent characteristics, PIXE offers great potential for trace element analysis in the …

Scanning Electron Microscope Study Of Wohlfahrtia Magnifica (Schiner, 1862) (Diptera: Sarcophagidae) I. Structures With Parasitic And Possible Taxonomic Meaning, I. Ruíz-Martínez, M. D. Soler-Cruz, R. Benítez-Rodríguez, J. M. Pérez-Jiménez, C. Adalid-Fuentes, M. Díaz-López

Scanning Microscopy

The larval development of Wohlfahrtia magnifica (the most important dipteran causing sheep myiasis in the Palearctic region) has been studied by means of scanning electron microscopy. The ultrastructure of mouth-hooks, oral ridges, labial lobes, body spines and anterior and posterior peritremes is described for the first time. Their possible adaptations to a parasitic lifeway are also discussed. Thus, the use of new structures in the Sarcophagidae taxonomy is proposed from the point of view of their ultrastructure and adaptative morphology.

Responses Of Astrocytes In Culture After Low Dose Laser Irradiation, David T. Yew, D. R. Zheng, C. Au, W. W. Y. Li

Scanning Microscopy

The effect of Helium-Neon low dose laser on astrocytes was investigated in cultures of isolated astrocytes from albino neonatal rats. The laser appeared to inhibit the growth of astrocytes as exemplified by the smaller sizes of the cells and the decreased leucine uptake in each cell after treatment. Temporary decrease in the number of mitoses was also observed, but this trend was reversed soon after. Electron microscopic studies revealed an increase in buddings from cell bodies and processes (branches) after irradiation.

Detector Arrays In Confocal Scanning Microscopes, T. Wilson

Scanning Microscopy

We consider the use of detector arrays in scanning microscopes and show that confocal operation may be achieved in a variety of ways. We base our analysis on a consideration of the form of the optical transfer function or transmission cross coefficient. This reveals that the Fourier transform of the detector sensitivity function is the function of importance. It is not necessary that this function be constant over the whole space and hence a variety of detector sensitivity functions will give fully confocal imaging. The traditional method of a limiting point-like detector is a special case, but one which has …

Crystal Growth Of Calcium Oxalate Monohydrate And Calcium Carbonate From Dilute Solutions, Sergio Deganello, Livia Di Franco

Scanning Microscopy

By controlling evaporation, calcium carbonate (calcite) is precipitated together with calcium oxalate monohydrate from equimolar (1 x 10^-5 M) solutions of calcium chloride and sodium oxalate under decreasing (37.5° - 32.7°C) and increasing temperature (22°-42°, 22°-45°, 22°-50°C), and initial pH's of 6.6 and 6, respectively. If, however, the pH of the solutions is, respectively, 8 and 8.5 and the temperature is 32°C, oxalate breaks down to carbonate and calcium precipitates solely as calcite. This process materializes as the pH of both solutions initially adjusts to about 7.5. Both the quality and the size of the crystals of calcite and …

Particle Induced X-Ray Emission Elemental Analysis: Sample Preparation For A Versatile Instrumental Method, N. F. Mangelson, M. W. Hill

Scanning Microscopy

Particle induced X-ray emission (PIXE) has found extensive application as a multi-element analysis tool. The energetic nature of both the incident particle beam and the emitted characteristic X-rays has lead to considerable versatility in regard to samples which may be analyzed by the PIXE technique. This paper does not deal with the theory, equipment, or data analysis for PIXE, but it should bring to the reader a broad perspective of methods for sample preparation and should point the way into the literature where more complete details are given. Both physical and chemical processes for sample preparation are outlined. Preparation often …

Evidence That A Major Portion Of Cellular Potassium Is "Bound", Ivan L. Cameron, W. Elaine Hardman, Keithley E. Hunter, Christine Haskin, Nancy K. R. Smith, Gary D. Fullerton

Scanning Microscopy

In this report we briefly review recent evidence which shows that a substantial proportion of intracellular K⁺ is "bound" or perturbed from the physicochemical properties expected in dilute aqueous solutions. In addition, we present evidence from electron probe x-ray microanalysis of thin cryosections of cells which indicates that the binding of K⁺ to anionic groups either carboxyl groups (HCO₂) on proteins or to phosphate groups in creatine phosphate (CrP) , in adenosine triphosphate, (ATP), in protein and in nucleic acids, are the main determinants of the maintenance of (as differentiated from the generated of) the well …

Composition Depth Profiles Of High Temperature Superconducting Materials By Energetic Elastic Backscattering, C. R. Gossett

Scanning Microscopy

A review is given of the application of high energy elastic backscattering spectrometry techniques for profiling high-temperature superconducting (HTSC) materials in thin film form. The use of higher bombarding ion energies provides most of the advantages of the more common lower energy or Rutherford backscattering (RBS) but additionally allows profiling to a greater thickness and, by a much larger sensitivity for light elements, permits profiling carbon and oxygen in the presence of heavier substrates. Examples for HTSC materials are given.

Studies Of Irritant Reactions On Epidermis: The Application Of Energy Dispersive X-Ray Microanalysis, Magnus Lindberg

Scanning Microscopy

Modern man is exposed to an increasing amount of chemicals in the environment. The skin is a complex tissue with regards to both structure and function. Contact with external stimuli can lead to various responses in the skin depending on the type of stimuli, the dose and time of exposure and the status of the exposed individual. The electron probe microanalytic technique can be used to obtain information on physiological alterations within the skin and especially the epidermis when the normal homeostasis is disturbed by contact with external stimuli. The present paper presents a review of some aspects of contact …