Life Sciences Commons^™

A Morphological Study Of The Venom Apparatus Of The Spider Allopecosa Fabilis (Araneae, Lycosidae), Külti̇ği̇n Çavuşoğlu, Meltem Maraş, Abdullah Bayram

Turkish Journal of Biology

The morphological structure of the venom apparatus of Allopecosa fabrilis was studied using scanning electron microscopy (SEM). The venom apparatus is situated in the prosoma and is composed of a pair of chelicerae and venom glands. Each chelicera consists of 2 parts, a stout basal part covered by hair, and a movable fang. A venom pore is situated on the subterminal part of the fang. Just below the fang, there is a cheliceral groove next to the teeth. Each side of the groove is covered with cuticular teeth. The venom glands are large and roughly cylindrical. Each gland is surrounded …

Application Of Monte Carlo Simulations To Critical Dimension Metrology In A Scanning Electron Microscope, Jeremiah R. Lowney

Scanning Microscopy

The state of the art in Monte Carlo simulations of scanning electron microscope (SEM) signals is reviewed. Two Monte Carlo computer codes were written to simulate the transmitted-, backscattered-, and secondary-electron signals from targets in a scanning electron microscope. The first, MONSEL-11, is applied to semi-infinite lines produced lithographically on multi-layer substrates. The second, MONSEL-111, is an extension to fully three-dimensional targets. Results for a 1 μm step, etched in a silicon substrate are compared with experimental data. The comparisons show that it is possible to obtain edge locations to an uncertainty of less than 10 nm. Simulations were performed …

Cathodoluminescence Contrast Of Localized Defects Part Ii. Defect Investigation, K. L. Pey, J. C. H. Phang, D. S. H. Chan

Scanning Microscopy

Cathodoluminescence contrast from defects with different geometrical and electronic properties have been studied using the numerical model developed in Part I. The contrast of a localized subsurface defect exhibits a maxima at a specific beam energy E_max which corresponds to the depth of the defect. The contrast of a dis-location which intersects the top surface perpendicularly is a decreasing function of beam energy. The differences in the image profiles of the two different kinds of defects allow the two types of imperfections to be distinguished. In addition, the resolution of a subsurface defect at beam energies lower than E …

Investigation Of Dislocations In Gaas Using Cathodoluminescence In The Scanning Electron Microscope, K. L. Pey, J. C. H. Phang, D. S. H. Chan

Scanning Microscopy

Electrically active dislocations in Si-doped {100} GaAs substrates were observed using the cathodoluminescence (CL) technique in the scanning electron microscope (SEM). CL contrast profiles were experimentally obtained from the dislocations at different beam energies. Based on the CL model for localized defects in semiconductors developed earlier by Pey, the depths of the dislocations were found by locating the beam energy at which maximum CL contrast occurred. A preferential etching technique for {100} GaAs was employed to reveal the dislocations and to measure their depths. The etched depths obtained were compared to the predicted results from the theoretical model developed. The …

Scanning Electron Microscopic Studies Of The Palatine Mucosa And Its Microvascular Architecture In The Rat, S. Sugioka, H. Ike

Scanning Microscopy

Detailed observations were made on the structure and microvasculature of the palatine mucosa of the rat by means of microvascular corrosion casts and epithelium-digested specimens using scanning electron microscopy. The rat palate was divided into four regions according to the characteristics of the palatine plicae. In the atrial region, no transverse palatine plicae were present, but there were longitudinal ridges and folds in the median area. These structures contribute to the transportation of rough and grainy foods with the assistance of the hairy buccal part. Capillary loops in the ridge and folds appeared as continuous, sagittally elongated loops. In the …

A Simulation Model For Electron Irradiation Induced Specimen Charging In A Scanning Electron Microscope, D. S. H. Chan, K. S. Sim, J. C. H. Phang

Scanning Microscopy

A numerical model has been formulated to simulate the dynamics of specimen charging in a scanning electron microscope. In this model, the electric field due to imposed boundary conditions and fixed charges is solved by the finite element method. The empirical electron yield data are stored in "Universal Yield Curves (UYC)". These UYCs control the generation of secondary and backscattered electrons from various materials. The electrons emitted from electron-solid interactions are tracked using a leapfrog integration scheme. Excess charges generated on the surface of electrically floating solids are assigned to numerical grids using a linear charge redistribution scheme. The validity …

An Energy Dependent Model For Type I Magnetic Contrast In The Scanning Electron Microscope, W. K. Chim, D. S. H. Chan, J. C. H. Phang, T. S. Low, S. Thirumalai

Scanning Microscopy

The modelling of the magnetic contrast phenomenon in the scanning electron microscope (SEM) is important in understanding the physics of the contrast mechanism and the associated signal detection. In this paper, we report an improved analytical model for Type I magnetic contrast calculations using an approximate form of the Chung and Everhart secondary electron (SE) energy distribution. Previous studies have neglected this factor by assuming a mono-energetic model in order to simplify the calculations. This new model can be used to study different material specimens by appropriate choice of the work function and field-distance integral. The effect of energy filtering …

Scanning Electron Microscopy Of Age-Related Changes In The C57bl/6j Mouse Cochlea, Kunihiro Mizuta, Osamu Nozawa, Hirofumi Morita, Tomoyuki Hoshino

Scanning Microscopy

Hair cells and nerve fibers inside the organ of Corti of the C57BL/6J mouse, which is known as the precocious presbycusis model, were studied using the scanning electron microscope. For this study, we used thick serial sections cut from celloidin blocks.

In the 5-week-old mice, hair cell loss was not seen. The upper tunnel radial fibers crossed the upper part of the tunnel of Corti and entered the Nuel's space between the outer pillar cells. The fibers varied in diameter and showed many varicosities. The basilar fibers emerged into the tunnel of Corti beneath the upper tunnel radial fibers …

Calculation Of A Topographic Contrast In The Scanning Electron Microscope, M. Kotera, T. Fujiwara, S. Yamaguchi, H. Suga

Scanning Microscopy

A direct simulation of electron scattering in solids is developed. Using this simulation, a topographic contrast found in the scanning electron microscope is quantitatively discussed. The surface topography studied here is a rectangular rod pattern and a rectangular groove pattern at an infinite horizontal plane surface of Al. We quantify characteristics of the secondary electron image and of the backscattered electron image at the topography. The intensity profile at the bottom surface of the groove pattern is roughly approximated by an analytical model.

Efficiency Of The Secondary Electron Detector In The Scanning Electron Microscope, Zbigniew Czyzewski, David C. Joy

Scanning Microscopy

The efficiency of the secondary electron detector in the scanning electron microscope (SEM) is one of the most important factors affecting the imaging process of the SEM. To compute the detector efficiency, the electrostatic field inside a specimen chamber must be known. A simple way of performing such calculations is to use a spreadsheet program which has a built-in capability of storing and performing some operations on three-dimensional matrices. Using a spreadsheet program makes it possible to solve the Laplace equation and calculate electron trajectories in geometrically complex electrostatic fields. This technique is applied to the estimation of detector efficiency …

Microvascular Architecture Of The Filiform Papillae In Primates And Insectivores, S. Okada, Y. Ohta, N. Matsukawa, S. Sugioka

Scanning Microscopy

The microvascular architecture of filiform papillae was investigated under a scanning electron microscope in man, Japanese monkeys, common squirrel monkeys, common marmosets, common tree shrews, large Japanese moles and dwarf shrews utilizing microvascular corrosion casts. Filiform papillae were circularly arranged in primates, and each of them was supplied by a hairpin capillary loop. These papillae sometimes were aggregated. The filiform papillae of Japanese monkeys exhibited markedly locational differences on the lingual dorsum and were supplied by circularly arranged capillary loops or by an intrapapillary capillary network. Small filiform papillae were located on an epithelial eminence in the lingual radix, each …

Modelling Techniques For The Quantification Of Some Electron Beam Induced Phenomena, Wk Chim, Dsh Chan, Ts Low, Jch Phang, Ks Sim, Kl Pey

Scanning Microscopy

This paper presents simulation models for quantifying the voltage contrast, cathodoluminescence and indirect specimen charging phenomena in the scanning electron microscope (SEM). The voltage contrast model comprises an electric field computation program using the finite-element approach, and a secondary electron trajectory tracking algorithm employing a linear electric field assumption. This trajectory tracking algorithm is more accurate than the conventional electron trajectory tracking algorithms which make use of a constant electric field assumption within each computation step. Using this model, results of qualitative voltage contrast effects on secondary electron trajectories in the specimen chamber of the SEM are shown. This model …

Scanning Electron Microscopic Studies Of The Oral Mucosa And Its Microvasculature: A Review Of The Palatine Mucosa And Its Microvascular Architecture In Mammals, Y. Ohta, S. Okada, I. Toda, H. Ike

Scanning Microscopy

The present paper deals with the microvascular architecture of the palatine mucosa in primates, camivorae, and rodentia utilizing microvascular corrosion castings and epithelium-separated specimens.

The submucous vascular network is under-developed since the bard palatine mucosa was designated the mucoperiosteum, except some areas. The palatine venous plexus appears to show regional differences with animal species differences. The well-developed plexus is observed to be two-layered and may contribute to the process of regurgitation of rough food and assist in mastication with the palatine plicae. Formation and patterns of the arterial network in the lamina propria are in a close relation with connective …

An Improved Method For Preparing Microvascular Corrosion Casts Of Rat Embryos, S. Yoshida, J. Chiba

Scanning Microscopy

This paper presents an improved method for preparing microvascular corrosion casts of rat embryos (day 16.5-21.5). Special attention was paid on the viscosity of the casting material, the method of mechanical restraint, and the subsequent drying of the casts. The embryos were perfused with Mercox resin diluted with 25% methyl methacrylate monomer followed by undiluted Mercox resin to avoid outflow of resin from the vasculature after perfusion. The specimens were mounted on a stainless steel plate with self-curing resin to prevent flotation, mechanical damage, and collapse of the cast specimens following preparation. After digestion and washing, the cast specimens were …

Image Segmentation Applied To Scanning Electron Microscopy Multi-Images Of Weathered Stones Of Monuments, M. Rautureau, R. Harba, G. Jacquet

Scanning Microscopy

This paper describes a three complementary images processing method. The three images are coming from a scanning electron microscope (SEM) during the analysis of a particular stone: the Tuffeau used in most monuments of the Loire valley (France). The goal is to separate two classes of particles (calcareous and siliceous) from the porosity to give more information to experts who evaluate the damage of weathering on monuments. A specific process is developed: a first threshold on the good quality image allows separation of particles from porosity. Then, the complementarity of the three images gives the two other thresholds. Granulometry, percentages …

The Effect Of Colcemid On The Heat Survival Of Mitotic V79 Chinese Hamster Cells, J. G. Szekely, G. P. Raaphorst, A. U. Lobreau, S. Delaney, E. I. Azzam

Scanning Microscopy

V79 Chinese hamster cells were collected by colcemid addition to study the effect of heat on mitosis. When they were heated at 42°C and 45°C in the presence of 0.06 μg/mL colcemid, cell survival increased over the control samples, which were heated in ordinary medium. Scanning electron microscopy showed that cells heated to 45°C in the presence or absence of colcemid had fewer microvilli on the surface, but they did not have increased bleb formation. Transmission electron microscopy showed that the chromatin was diffuse in the heated cells and the kinetochores were indistinct. The mitochondria in the heated cells were …

Sphincters In The Rat Pulmonary Veins. Comparison Of Scanning Electron And Transmission Electron Microscopic Studies, S. Aharinejad, P. Böck, A. Lametschwandtner, P. Franz, W. Firbas

Scanning Microscopy

The microvasculature of the rat lung was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of vascular corrosion casts and tissue sections. Particular emphasis was placed on postcapillary venules, pulmonary venules and small pulmonary veins (small interlobular veins).

Casts of lung capillaries appeared inconspicuous with smooth surface. On the casts of pulmonary venules and small pulmonary veins, by contrast, series of narrow annular constrictions, present at regular distances of 20-25 μm, were seen. These constrictions may be drastic, narrowing down the caliber of the vessel up to 50%. In the constrictions the marks of circularly running tubular …

The Vascularization Of The Digestive Tract Studied By Scanning Electron Microscopy With Special Emphasis On The Teeth, Esophagus, Stomach, Small And Large Intestine, Pancreas, And Liver, S. Aharinejad, A. Lametschwandtner, P. Franz, W. Firbas

Scanning Microscopy

The periodontal vessels in adult rats show a ladder-like pattern; in guinea pigs molars, by contrast, they present a honey-comb pattern. The vascular architecture in human teeth seems to be similar to that of rabbits. In guinea pigs, rats, rabbits and humans esophagus circumferential vessels give off perforating vessels. In human esophagus the number and diameter of the vessels in the submucous venous plexus decrease from proximal to distal. In the stomach the subepithelial capillary network shows a honey-comb pattern reflecting the arrangement of the gastric pits. A local portal system between the gastric glands and the surface mucosal cells …

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 …

Electron Microscopy Of Lipid Deposits In Human Atherosclerosis, G. Pasquinelli, P. Preda, M. Vici, M. Gargiulo, A. Stella, M. D'Addato, R. Laschi

Scanning Microscopy

The filipin probe associated with tannic acid stain was used to study intra-and extracellular lipids in surgically removed human atherosclerotic lesions (n = 20). In particular, intimal thickenings, fatty streaks and fibrolipidic plaques have been investigated by using mainly transmission and scanning electron microscopy. In the intimal thickenings, the lipid deposits were mainly localized in the subendothelial space as homogeneously sized particles (40-140 nm) and more heterogeneous uni-multilamellar vesicles (35-700 nm). Intermediate lipid forms were also observed. In the fatty streaks, the lipid deposits were intracellular and mainly observed in cells with a monocyte/macrophagic phenotype. Lipid inclusions, lipid lysosomal bodies …

Bacillus-Shaped Deposits Composed Of Hexahedrally Based Crystals In Human Dental Calculus, T. Kodaka, A. Hirayama, K. Miake, S. Higashi

Scanning Microscopy

In human supra- and subgingival calculus, bacillus-shaped deposits showing various rocky-pile forms composed of hexahedrally based crystals were observed by scanning electron microscopy. The crystal size measured approximately 0.1 - 1.5 μm. The electron probe microanalysis always detected calcium, phosphorous, and magnesium. Their molar ratios resembled those of magnesium-containing whitlockite and moreover the crystals also gave the electron diffraction pattern of whitlockite. The bacillus-shaped deposits happened to coexist with the intracellular calcifying microorganisms, furthermore, oral microorganisms partially replaced by the hexahedrally based crystals were found. The crystal deposits were never seen in the surface layers of calculus exposed to the …

Endothelial Injury In Human Atherosclerosis, G. Pasquinelli, A. Cavazza, P. Preda, A. Stella, B. I. Cifiello, M. Gargiulo, M. D'Addato, R. Laschi

Scanning Microscopy

A light and electron microscopic investigation (scanning and transmission electron microscopy) was performed on 51 human atherosclerotic carotid lesions. The purpose of this study was to establish whether features of endothelial injury such as those described in animals occur in man and whether these features can be related to specific stages of human atherosclerosis.

Irrespective of their histological appearance the atherosclerotic lesions were covered with endothelium which showed non-specific changes in cell shape and size. However, all complicated lesions appeared denuded. Moreover, a peculiar interaction of endothelium with monocytes and lymphocytes as well as blood components (e.g., fibrin and lipoproteins) …

Detectors For Quantitative Electron Beam Voltage Measurements, A. R. Dinnis

Scanning Microscopy

Qualitative voltage contrast is produced without difficulty in any SEM. Complete separation of the voltage contrast from other sources of contrast is not a straightforward matter because of the nonlinear relations between the phenomena causing contrast and the video signal.

Quantitative measurements depend on the availability of electron energy analysers which can detect accurately the shift in secondary electron energies due to potentials appearing on integrated circuit tracks, without being affected by transverse fields due to potentials on other conductors or insulators. The principles underlying existing detectors are explained, their effectiveness assessed, and a new form of electron detector is …

The Influence Of Analyser Geometry Effects In Scanning Electron Microscope Voltage Contrast Measurements, Daniel S.H. Chan, Teck Seng Low, Wai Kin Chim, Jacob C. H. Phang

Scanning Microscopy

A computer simulation model used to study specimen dependent and analyser geometry dependent effects is described in this paper. With this model, the influence of the specimen dependent effect on quantitative voltage contrast measurements can be isolated from the analyser geometry dependent effect. Linearization error voltages in quantitative voltage contrast measurements arising from the individual influences of the specimen dependent and analyser geometry dependent effects are presented. The results show that the error component due to very narrow analysers dominate the total linearization error. The same situation arises when the voltage measurement point on the specimen is very near to …

Bovine Aorta Endothelial Cell Incubation With Interleukin 2: Morphological Changes Correlate With Enhanced Vascular Permeability, Corazon D. Bucana, Joann Trial, Audrey C. Papp, Kenneth K. Wu

Scanning Microscopy

Interleukin 2 induced alterations in the morphology of bovine aortic endothelial cells in vitro. The changes observed in confluent cultures of bovine aortic endothelial cells included retraction and elongation of eel ls leading to enlarged gaps between cells quantified by image analysis. Purified IL-2 (1 U/ml medium) increased the gaps between endothelial cells 3-4-fold compared with control cultures. The effect was transient, since the cells reverted to their original morphology 6-12 hours after the removal of lL-2. Correlative scanning electron microscopy (SEM) studies using fresh bovine aorta showed a dose-dependent alteration of the endothelial surface by IL-2 characterized by rounding …

Response Of Laryngeal And Tracheo-Bronchial Surface Lining To Inhaled Cigarette Smoke In Normal And Vitamin A-Deficient Rats: A Scanning Electron Microscopic Study., P. K. Jeffery, A. P. R. Brain, P. A. Shields, B. P. Quinn, T. Betts

Scanning Microscopy

The effects on surface morphology of airway epithelium of cigarette smoke (CS) inhalation alone (experiments one and two) or of CS in combination with hypovitaminosis A (experiment two) was investigated using specific pathogen free rats. Eight morphologically distinct cell types were distinguished overall. Apart from atypical squamous lesions each of the other cell types could be found in varying proportions in all experimental groups. CS alone caused an increase in the frequency with which intra-lumenal mucus was seen and an increase in the occurrence of secretory cells of types IV (i.e.,'merocrine') and V (i.e.,'apocrine'). In experiment one, the area of …

Scanning Electron Microscopy Of Oral Mucosa In Vivo And In Vitro: A Review, Kristina Arvidson, Roland C. Grafström, Anders Pemer

Scanning Microscopy

The oral mucosa is classified by function into lining, masticatory and specialized oral mucosa, with regional structural adaptation. In this review, the surface structures of the human oral mucosa have been studied in the scanning electron microscope (SEM). Regional variations in regard to keratinization, cell arrangements and microplications with related specific structures observed in SEM are described and correlated with the appearance of similar areas observed in the light microscope. Furthermore, human oral tissue and cell cultures have also been studied. These systems offer usable and complementary models for performing similar studies in vitro under controlled experimental conditions. We now …

An Electron Beam Tester With Dispersive Secondary Electron Energy Analyser, P. Kruit, L. Dubbeldam

Scanning Microscopy

The design principles of a new, experimental e-beam tester are described. Using the magnetic field of an immersion objective lens the secondary electrons are guided to an energy analyser between the condenser lenses and the objective lens. The latter can now have a short working distance and small aberrations. The electron energies are analysed by a combination trochoidal motion - retarding field analyser, which enables detection of the faster secondary electrons on one detector and detection of the slower secondary electrons on a second detector. The benefit of this set up is a possibility for voltage contrast isolation, normalization with …

Low Energy Electron Diffraction With Microscopic Resolution, J. Kirschner, T. Ichinokawa, Y. Ishikawa, M. Kemmochi, N. Ikeda, Y. Hosokawa

Scanning Electron Microscopy

We report on the development of a Scanning Low Energy Diffraction Microscope, operating in the range of 250 to 1000 eV primary energy. By discriminating against inelastically scattered electrons, low energy electron diffraction (LEED) patterns are obtained from areas of about 100 nm in size. By selecting a particular diffracted beam dark-field images of the surface structure are obtained in the scanning mode. Examples are given for polycrystalline Si and clean and adsorbate covered Si (111) surfaces.

Charging Effects In Low-Voltage Scanning Electron Microscope Metrology, M. Brunner, R. Schmid

Scanning Electron Microscopy

Low voltage operation of the scanning electron microscope is being increasingly used to avoid negative charging in e-beam inspection and metrology. Positive charging effects, however, may still disturb the measurement accuracy even with low primary beam energies. Current investigations have revealed that no errors due to positive charging occur on resist structures on semiconductor substrates. But samples with metal structures on insulating substrates do involve disturbing effects due to positive charging. The difference in behavior between these groups of samples is attributed to the fundamental difference between insulator and conductor charging. This difference is due to different field geometries on …