Life Sciences Commons^™

Conventional And High Resolution Scanning Electron Microscopy Of Biological Sectioned Material, C. Scala, G. Cenacchi, P. Preda, M. Vici, R. P. Apkarian, Gianandrea Pasquinelli

Scanning Microscopy

Intracellular structures of embedded biological tissues (rat kidney, myocardium and small intestine) were observed by conventional-scanning electron microscopy (C-SEM) and high-resolution scanning electron microscopy (HR-SEM) after glass knife sectioning. C-SEM of semi -thin sections of material processed the same way as conventional transmission electron microscopy (TEM) provided strong backscattered electron (BSE)-dependent, two-dimensional secondary electron images (SEI(-)) which precisely integrated and further extended previous light microscopy (LM) observation of the same specimen. In addition, the three-dimensional (3-D) arrangement of intracellular organelles was appreciated using a mixture of acetone-soluble acrylic resin in place of epoxy resin embedding. Since the identification of such …

Development And Use Of A Pneumoconiosis Database Of Human Pulmonary Inorganic Particulate Burden In Over 400 Lungs, Jerrold L. Abraham, Bryan R. Burnett, Andrew Hunt

Scanning Microscopy

Over 400 cases with data from in situ electron microprobe quantitation of non-fibrous inorganic particles (e.g., silica, alumino-silicates, talc, metals) in pulmonary tissue sections, and data from quantitative digestion analyses for fiber content (e.g., asbestos, silica, alumino-silicates, man-made fibers, talc) comprise an extensive microcomputer data set of lung particle burden. When allied with demographic and histopathologic information the result is a comprehensive database of occupational pulmonary pathology. Examples of the kinds of information which can be extracted from the database include: 1) summary information on the types sizes and associations of particles in lungs with a variety of exposures, 2) …

Scanning Electron Microscopic Study Of Pulp Stones In Human Permanent Teeth, O. Le May, J. C. Kaqueler

Scanning Microscopy

Scanning electron microscopy was used to examine pulp stones which are small calcified formations found in the coronal and/or radicular part of the dental pulp. Pulp stones range considerably in size and shape. Most are round or oval but others can be irregular and may correspond to a reduced duplicate of the pulp chamber anatany. Both free and attached pulp stones were observed. The surface aspect was variable and frequently exhibited large resorption zones. Three characteristic features were observed on fractures a) no characteristic organization where the mineralized mass is compact and hanogeneous, b) a concentric architecture around an initiating …

A Scanning Electron Microscopic Study Of The Morphology Of Scyphidia Physarum Lachmann, 1856 (Ciliophora: Peritrichida), A. Warren

Scanning Microscopy

The morphology of Scyphidia physarum was investigated by scanning electron microscopy (SEM). Both contracted and uncontracted zooids were examined. The pellicular striations encircled the body at mean intervals of 1.1 µm. Pores were randomly distributed over the body surface with a mean density of 21 pores per 100 µm 2. The telotroch band was represented by three closely spaced striations. The adoral ciliature consisted of a single row of cilia in the haplokinety and three rows in the polykinety. The two sets of cilia were separated by a pellicular ridge. At the end of each row of cilia was a …

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 …

Scanning Electron Microscopic Analysis Of Mineral Fiber Content Of Lung Tissue In The Evaluation Of Diffuse Pulmonary Fibrosis, Victor L. Roggli

Scanning Microscopy

The mineral fiber content of lung parenchyma in 24 cases of diffuse pulmonary fibrosis of unknown cause was determined by scanning electron microscopy and compared with that of 36 autopsy cases of histologically confirmed asbestosis and 20 autopsy cases of patients with normal lungs . Fibers were isolated from the lung using a hypochlorite digestion technique and collected on the surface of a polycarbonate filter. In addition, the types of fibers present (asbestos vs. other mineral fibers) were determined by energy dispersive x - ray analysis (EDXA). When the histologic grade of fibrosis in the cases of asbestosis was compared …

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 …

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 …

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 …

Crystal Morphology Of Shortenings And Margarines, P. Chawla, J. M. Deman, A. K. Smith

Food Structure

An improved method is proposed for isolation of fat crystals with isobutanol, followed by fixation using osmium tetroxide vapours or cryo-fixation and visualization in the Scanning Electron Microscope (SEM). The cryo-fixation method revealed the presence of well defined needle-shaped or rod-shaped fat crystals. The osmium fixed crystals did not appear as distinct. The crystals existed as single crystals, platelets and spherulites. Polarized light micrographs did not show the details of the crystal morphology that were observed in the SEM.

Radiation Cataractogenesis Induced By Neutron Or Gamma Irradiation In The Rat Lens Is Reduced By Vitamin E, W. M. Ross, M. O. Creighton, J. R. Trevithick

Scanning Microscopy

Although cataract of the eye lens is a known late effect of ionizing radiation exposure, most of the experimental work to date has concentrated on single, acute high doses or multiple, fractionated, chronic exposures. Many papers have dealt with biochemical alterations in metabolism and cellular components, with microscopic and electron microscopic lesions to the epithelial and cortical layers, and with clinical cataract formation. However, the minimum cataractogenic dose for rats has for many years been considered to be about 2 Gy for a single, acute dose of low LET radiation.

Our purpose in designing this pilot study was three fold: …

The Development Of Dendritic Carbides In A Dual-Phase Martensitic/Ferritic Steel, E. Materna-Morris

Scanning Microscopy

Several ferritic-martensitic laboratory melts with a varying chromium content of 9-14 wt.% and delta-ferritic quantities ranging from 0-25% were investigated by means of impact-testing. The negative influence of delta-ferrite (>0.5%) on the mechanical properties can be explained by the formation of dendritic M₂₃C₆-precipitates around the delta-ferrite grains. The development of these dendrites was studied as a function of the cooling kinetics using dilatometric and metallographic measurements and by SEM (scanning electron microscopy) and TEM (transmission electron microscopy) investigations.

Microstructure Of Peanut Seed: A Review, Clyde T. Young, William E. Schadel

Food Structure

Mature peanut seed microstructure of importance to the food industry is examined with regard to: (1) anatomy and cytology of peanut seed; (2) the effects of environment on peanut seed; and (3) the effects of various processing procedures on peanut seed. Current peanut seed microstructure research by the authors is directed toward evaluation of the quality of processed peanuts including using TEM, SEM and LM to evaluate the effects of different times of oven roasting at the same temperature, and a method for evaluating quality of homogenization of broken cell and tissue fragments, protein bodies and starch in stabilized peanut …

Human Hair Morphology: A Scanning Electron Microscopy Study On A Male Caucasoid And A Computerized Classification Of Regional Differences, W. M. Hess, R. E. Seegmiller, J. S. Gardner, J. V. Allen, Susan Barendregt

Scanning Microscopy

The present study was performed to provide a better understanding of the morphological variations of mammalian hair. Terminal hair samples were obtained from different regions of the body of the same Caucasian male. All hair samples were either cleaned or treated before being examined with scanning electron microscopy. As human scalp hair grew it appeared small like lanugo hair, but the increase in diameter appeared to have been relatively rapid. As hair increased in diameter the appearance of the scales changed. Neck hair was slightly smaller in diameter than scalp hair, and axillary hair was slightly smaller in diameter than …

Coal Mineral Analysis: A Check On Inter-Laboratory Agreement, G. S. Casuccio, F. A. Gruelich, G. Hamburg, F. E. Huggins, D. A. Nissen, J. M. Vleeskens

Scanning Microscopy

Four laboratories co-operated to test repeatibility and reproducibility of the semi-quantitive Coal Mineral Analysis (CMA) method. CMA is an instrumented image analysis method which identifies mineral particles in coal by chemical composition (energy dispersive X-ray spectroscopy) and size (scanning electron microscopy). The repeatability of weight percent data was better than 0.2 relative standard deviation for most minerals constituting more than five percent of all coal minerals. The type of mineral had no effect on repeatability. Errors arising from counting statistics were shown to be the major source of bias at a given instrument setting.

Inter-laboratory data for the major minerals …

Healing Of Prosthetic Arterial Grafts, G. Pasquinelli, A. Freyrie, P. Preda, T. Curti, M. D'Addato, R. Laschi

Scanning Microscopy

Numerous synthetic biomaterials have been developed as vascular substitutes. In vitro, ex vivo and in vivo studies have demonstrated that in animals, selected materials, i.e., Dacron and ePTFE (expanded polytetrafluoroethylene) grafts, are successfully incorporated in both the large and the small caliber host arteries through a process which is generally referred to as graft healing. Morphologically, this process consists of a series of complex events including fibrin deposition and degradation, monocyte-macrophage recruitment and flow-oriented cell-layer generation, this last event being the complete endothelialization of the arterial substitute.

In contrast to experimental animals, the flow surface of synthetic vascular grafts remains …

Fracture Toughness And Fractography Of Dental Cements, Lining, Build-Up, And Filling Materials, H. J. Mueller

Scanning Microscopy

The plane strain fracture toughness (K_1C) at 23°C and the fractography of zinc phosphate and zinc polycarboxylate cements, buffered glass ionomer liner, amalgam alloy admixed glass ionomer build-up material, and glass ionomer, microfilled and conventionally filled bis-GMA resin composite filling materials were analyzed by elastic-plastic short-rod and scanning electron microscopy methodologies. Results indicated that significant differences occurred in their K_1C' s from the lowest to the highest in the following groups of materials, (i) buffered glass ionomer, (ii) zinc phosphate, glass ionomer, zinc polycarboxylate, and alloy mixed glass ionomer, (iii) microfilled resin, and (iv) conventionally filled …

Scanning Electron Microscopy Of Immuno-Gold Labeled Antigens Associated With Bladder Cancer, E. De Harven, J. G. Connolly, Y. Wang, W. Hanna, G. Bootsma

Scanning Microscopy

Scanning electron microscopy (SEM), in the backscattered electron imaging (BEI) mode, has been used to study the topographical distribution of colloidal gold labeled antigens expressed on the luminal surface of the bladder urothelium in biopsies from three categories of patients: 1) normal controls; 2) patients with a history of bladder cancer but no pathological diagnosi s at time of cystoscopy; and 3) patients with overt transitional cell carcinoma (TCC) of various histopathological stages and grades. Cold cup biopsies were processed for immuno-SEM according to a previously described method. Antigens under investigation were: 1) ABH blood group antigens; and 2) those …

Morphology Of Polyanhydride Microsphere Delivery Systems, E. Mathiowitz, D. Kline, R. Langer

Scanning Microscopy

Scanning electron microscopy (SEM) was used to elucidate the mechanism of polymer degradation and drug release in polyanhydride microspheres. Three different fabrication methods — solvent removal, solvent evaporation, and hot melt microencapsulation — were used to prepare polyanhydride microspheres containing a variety of drugs. The morphology of these microspheres releasing drug in vitro and in vivo was studied by SEM and compared with degradation and release data measured by conventional methods. Microspheres prepared by the three techniques were shown to have distinctive morphological characteristics induced by the nature of the fabrication method. In addition, SEM analysis could be used to …

Osteoclast Cytomorphometry And Scanning Electron Microscopy Of Bone Eroded Surfaces During Leukemic Disorders, Daniel Chappard, Jean François Rossi, Régis Bataillle, Christian Alexandre

Scanning Microscopy

Tartrate resistant acid phosphatase (TRAP) is a reliable histochemical marker of osteoclasts when used on tissue sections of undecalcified bone. This paper presents an original morphometric analysis which can be done after histochemical identification of osteoclasts. These bone resorbing cells were demonstrated on undecalcified bone biopsies from control subjects and patients presenting a malignant disease of the lymphocyte B lineage. Computerized analysis of the osteoclastic population revealed that: (1) all TRAP positive cells along bone trabeculae belong to a osteoclastic population; (2) that B cell malignancies had an increased bone resorption. At the scanning electron microscopic level small resorption bays …

On The Varied Appearances Of The Human Placental Villous Surface Visualised By Scanning Electron Microscopy, G. J. Burton

Scanning Microscopy

Scanning electron microscopy enables extensive areas of the human placental villous tree to be viewed at high resolution in a relatively quick and easy manner. It is therefore an invaluable aid to the study of normal placental structure, and may have a potential role to play in pathological diagnosis. However, with increasing experience an awareness of the possible artefacts that may be introduced during fixation and tissue preparation is gradually developing. Some of these artefacts are common to other organs and applications of scanning electron microscopy, whereas others result from the unique structure and three-dimensional configuration of the placenta. Examples …

Plasmons In Scanning Transmission Electron Microscopy Electron Spectra, R. H. Ritchie, A. Howie, P. M. Echenique, G. J. Basbas, T. L. Ferrell, J. C. Ashley

Scanning Microscopy

A general self-energy formulation of the interaction between an electron in a scanning transmission electron microscope (STEM) and a localized target is given. We prove a theorem relating the probability of energy transfer to that calculated classically. Local dielectric theory of target excitation for various geometries is discussed. The problem of localization of initially unlocalized excitations in the valence band of solids is treated by transforming cross sections differential in momentum transfer into dependence on an impact parameter variable. We are thereby able to account for experimental data in scanning electron microscopy (SEM) that show high spatial resolution.

Particle Characteristics Of Flake-Cut Meat, P. R. Sheard, A. Cousins, P. D. Jolley, C. A. Voyle

Food Structure

The size of flake-cut meat is an Important quality determinant of comminuted meat products which. potentially. depends upon a large number of factors. Temperature and whether or not the meat is pre-broken have a major Influence on the resulting particle size distribution, as does aperture size. Meat flaked at -7'C produced two to three times more flakes than at -3' C. Under some conditions the particles produced were as little as 0.4 mm thick and characteristically were thicker at one end.

High speed photography, used to visualise the cutting action. Indicated that size reduction occurs In a controlled manner providing …

Light And Scanning Electron Microscopy Of The Peanut (Arachis Hypogaea L. Cv. Florunner) Cotyledon After Roasting, Clyde T. Young, William E. Schadel

Food Structure

Changes in the microstructure of peanut (Arachls ~ L. cv Florunner) cotyledons after roasting at a temperature of 160°C (16 min) were investigated with light and scanning electron microscopy. Major changes included: (1) pitting and pock -marking of the epidermis of the cotyledons caused by the escape of steam and on released during roasting; (2) loss of cellular organization of the cytoplasmic network surrounding the Jipid bodies, protein bodies, and starch grains ; (3) alteration of the structures of cytoplasmic network. lipid bodies, and protein bodies; and (4) heat destruction of some middle lamellae of cell - t o-cell junctions.

Microscopic Measurement Of Apple Bruise, N. K. Kim, Y. C. Hung

Food Structure

Microstructural differences between unbruised and bruised apple tissues were evaluated. Cell connections appeared to be looser in bruised tissue than in unbruised tissue. Bruised tissue exhibited more empty regions which are not occupied by cells than unbruised tissue. Empty reg ions in unbruised and bruised tissues were about 0.7 and 2.4 per mm2, respectively, comprising 0.7% and 2.7% of the respective total volume. Stereology is a body of mathematical methods relating three-dimensional parameters defining a structure to two- dimensional measurements. Two methods based on a stereological principle were also used to quantify the fraction of total volume occupied by cells. …

Scanning Electron Microscopy: Tissue Characteristics And Starch Granule Variations Of Potatoes After Microwave And Conductive Heating, J. Huang, W. M. Hess, D. J. Weber, A. E. Purcell, C. S. Huber

Food Structure

In order to determine cytological effects of microwave heating compared to conductive heating, whole potatoes were heated in a microwave oven in plastic bags for 0.5, 1 and 2 minutes and in boiling water for 5. 10 and 20 minutes. Both heating treatments caused swelling and partial disruption of starch granules. However, as observed with scanning electron microscopy, swelling patterns of starch granules were different in potatoes using the two heating processes. In conductive heating potatoes were heated from the outside to the inside. Microwave heated potatoes were heated fairly uniformly in different regions of tubers. The weight loss of …

Changes In The Rheology And Microstructure Of Ropy Yogurt During Shearing, J. A. Teggatz, H. A. Morris

Food Structure

Rheological and microstructural changes that occurred in ropy yogurt during shearing were observed. Yogurt made with an exopolymer-producing (ropy) strain of Lactobacillus delbrueckii subsp. bulgaricus and non-ropy strain of Streptococcus thermophilus was subjected to an increasing shear rate from 0-833 s-1 using a Haake Rotovisco RV2. Shear stress niticeably increased to a peak value and then decreased to a plateau value as the shear rate continued to increase. Samples taken at eight different shear rates were examined by scanning electron microscopy (SEM). At low shear rates, the exopolysaccharide (EPS) existed as a filamentous network attached to the lactobacilli and casein …

A Method For The Examination Of The Microstructure Of Stabilized Peanut Butter, Clyde T. Young, William E. Schadel

Food Structure

A method for light and scanning electron microscopy of damaged resting peanut seed tissue was adapted as a research tool for evaluating the microstructural features of commercially available stabilized peanut butter. This method was used in the present study to evaluate the degree of homogenization of stabilized peanut butter by examining the spatial relationship which exists among the microstructural features. Light and scanning electron microscopy of three commercially available stabilized peanut butters revealed varying degrees of homogenization of broken cell and tissue fragments, protein bodies, and starch grains within a matrix of stabilized oil.

Transmission And Scanning Electron Microscopy Of Peanut (Arachis Hypogaea L. Cv. Florigiant) Cotyledon After Roasting, Clyde T. Young, William E. Schadel

Food Structure

Changes in the microstructure of peanut (Arachis~ L. cv. Florigiant) cotyledon after roasting at a temperature of 160°C for 16 minutes were investigated with transmission and scanning electron microscopy. Thermal modifications were documented with photomicrographs of t he cytoplasmic network , protein bodies, starch grains and cell-to-cell junctions after oven roasting. These thermal modifications include disruption of the cytoplasmic network, distension of protein bodies, decreased stain affinity of starch grains , and disintegration of middle lamellae in some cell-t o-cell junctions.