Biology Commons^™

Ion-Induced Auger Emission From Solid Targets, Josette Mischler, Nicole Benazeth

Scanning Electron Microscopy

We present a review of the Auger emission induced from light elements (Mg, Al, Si) bombarded by ions of intermediate energy (1 keV - 200 keV). The different physical phenomena at the origin of Auger emissions are outlined, in particular the mechanism of molecular excitation responsible for the production of inner-shell vacancies in collisions between two complex particles and the processes of Auger decay and electron transport in the solid. Auger spectra partially consist of L₂₃VV electrons corresponding to decays in the bulk; this part is similar to that observed from electron-induced Auger spectra. Superimposed on this broad …

Mapping Solid Surfaces With A Raman Microprobe, P. M. Fauchet

Scanning Electron Microscopy

By combining an optical microscope with a standard Raman scattering apparatus, information on the structure, composition, homogeneity, and stress state of solids can be obtained with one micron resolution. After a discussion of the advantages and implementation of the technique, we examine specific applications mostly taken from our own work dealing with laser-solid interactions. In particular, we examine the structural modifications produced during laser annealing of semiconductors and laser induced damage of thin films.

Capacitive Coupling Voltage Contrast, S. Görlich, K. D. Herrmann, W. Reiners, E. Kubalek

Scanning Electron Microscopy

Capacitive coupling voltage contrast (CCVC) allows electron-beam testing of passivated integrated circuits (IC) without radiation damage or prior, time-consuming specimen preparation. This effect occurs when low primary electron energies are used and the electron yield of the passivation layer is greater than 1. Signal changes in the relevant interconnections are transferred to the passivation surface via capacitive coupling, but they vanish there within the storage time due to electron irradiation. A physical model explains the dependence of CCVC on three parameters: electron irradiation, the passivation material and the signals within the IC. Computer simulations based on this model describe the …

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.

Electron Detectors For Electron-Beam Testing Of Ultra Large Scale Integrated Circuits, S. C. J. Garth, D. F. Spicer

Scanning Electron Microscopy

The increasing density of components in integrated circuits imposes severe constraints on conventional electron beam testers. The use of electron detectors consisting of combined electrostatic and magnetic fields has demonstrated improved performance over conventional electrostatic detectors. Such detectors also ease many of the practical difficulties associated with electron beam testing of Ultra Large Scale Integration (ULSI) circuits. A detector using a single pole magnetic lens will be described and compared to detectors which use only electrostatic fields. The single pole lens detector has demonstrated superior performance to the electrostatic detector in terms of local field error and imaging resolution, allowing …

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 …

Auger Microprobe Temperature Profiles Of Contamination Residue On Single Crystal Ferrite Substrates, Christine Bisagni, Nina Veisfeld

Scanning Electron Microscopy

Single crystal manganese-zinc (MnO,ZnO.Fe₂O₃) ferrite wafers with a 50 Angstrom surface finish were subjected to a conventional cleaning procedure and then analyzed in a JAMP-10 Auger microprobe with an internal heating device. Three essential Auger peaks were monitored during the heating. Auger peak intensity vs. time profiles were obtained for the heating process. High vacuum heat treatment conditions were established for the preparation of these materials for use as substrates in UHV thin film growth.

Applications Of X-Ray Microanalysis To The Study And Conservation Of Ancient Glasses, S. Hreglich, M. Verita

Scanning Electron Microscopy

X-ray microanalysis can be successfully applied to the study of the chemical composition and weathering processes of ancient glass. The problems concerned with this kind of application are considered. A verification is conducted of the accuracy and sensitivity of this technique, which are sufficient to obtain useful information on technologies and raw materials used and consequently on the origin and dating of ancient glasses.

This analytical method also discloses meaningful data for the optimization of restoration and the choice of appropriate conservation operations.

High Resolution Scanning Auger Microscopy Of Mineral Surfaces, M. F. Hochella Jr., A. M. Turner, D. W. Harris

Scanning Electron Microscopy

There are a number of cases where scanning Auger microscopy can be used to determine the near-surface composition of minerals with extremely high lateral resolution. This involves collecting Auger spectra with reasonable signal to noise ratios without encountering significant beam induced charging or surface degradation, even if the beam is impinging on a grain less than 1μm in diameter. We typically use a 3 keV beam with less than 10 nA beam current on a sample surface that is tilted (to increase backscattered and secondary electron emission efficiency) and relatively flat. To further minimize surface degradation, vacuum levels are kept …

Correlative Scanning Electron Microscopy In The Study Of Human Gastric Mucosa, F. Bonvicini, M. C. Maltarello, P. Versura, D. Bianchi, G. Gasbarrini, R. Laschi

Scanning Electron Microscopy

We studied two aspects of the human gastric mucosa: - the surface morphology of mucous cells, as viewed by scanning electron microscopy (SEM); - the glycosidic components of intracellular mucins, characterized by means of lectins. The latter were conjugated with fluorescein isothiocyanate and with colloidal gold-silver for the visualization of the reaction products in light microscopy (LM) and in SEM (backscattered mode) respectively.

The surface morphology of mucous cells appears to be correlated to the secretory state.In gastric ulcers we found a prevalence of non-secreting cells. A decrease in glycosidic receptors for fucose-binding lectin and galactose-(l-3)-N-acetyl-galactosamine-binding lectin was also observed. …

The Use Of A Line Scan Ratemeter For The X-Ray Microanalytic Evaluation Of Membrane-Bound Histochemical Endproducts, Imre Zs.-Nagy, Valéria Zs.-Nagy

Scanning Electron Microscopy

Although X-ray microanalysis represents a useful tool for identifying electron dense histochemical end-products, quantitative microanalytic measurements are seriously hampered in the case of the activities of certain membrane-bound enzymes. For example, the electron histochemical methods revealing K⁺-dependent pNPPase activity result in a very fine, granular reaction product of lead phosphate. Therefore microanalytic, densitometric or similar evaluations of the reaction, even in semiquantitative terms are not practical by the usual procedures.

This paper describes a method of X-ray microanalysis of thick sections (0.5 μm) processed for K⁺-pNPPase, where a sufficient amount of lead is present for X-ray …

Quantitative Ion Microprobe Analysis Of The Rare Earth Elements In Minerals, Ghislaine Crozaz, Ernst Zinner

Scanning Electron Microscopy

The lanthanides or rare earth elements (REE) which are present in trace concentrations in rocks are most useful for investigating the origin of these objects. Of the microbeam techniques presently used to measure the REE concentrations of individual crystals, secondary ion mass spectrometry (SIMS) is the only method sensitive enough to allow the determination of REE abundances in most natural minerals. Usually, energy filtering is applied to remove all complex molecular interferences. All the REE, down to a level of ≤ 100 ppb, can be measured in spots 5 to 20 𝜇m in diameter. A growing number of studies involving …

Intrauterine Device (Iud) Associated Pathology: A Review Of Pathogenic Mechanisms, Waldemar A. Schmidt, Karmen L. Schmidt

Scanning Electron Microscopy

This paper summarizes our studies of IUD-related disease with those previously published by others. Our data are based upon 51 IUDs and 42 index cases of IUD-related disease demonstrating specific processes. Gross, dissecting microscope, scanning electron microscope and X-ray microanalysis examinations were made of selected IUDs and associated tissues. Tissue associated with the IUDs revealed inflammation in 59.4%, calcific material in 6.3% and no abnormality in 34.4%. JUD-associated tissue responses were accompanied by changes of the IUD; these changes involved deposition of substances upon the IUD surface and degradation of the JUD itself. Disintegration of the IUD, its string or …

Structural Features Of Isolated, Fractionated Bone Marrow Endothelium Compared To Sinus Endothelium In Situ, Seiji Irie, Mehdi Tavassoli

Scanning Electron Microscopy

Structural features of isolated, fractionated rat bone marrow endothelium were compared to those of marrow sinus endothelium in situ. Marrow endothelium was purified, first by density gradient sedimentation on Percoll and then subjected to centrifugal elutriation. Using antifactor VIII antibody staining (indirect immunofluorescent method), preparations of greater than 50% purified endothelium were obtained. By SEM, these cells were about 10 μm in size and showed smooth surface and numerous invaginations. These features were also observed in the in situ endothelium obtained by perfusion-fixation and freeze-cracking. In addition, in situ endothelium displayed numerous hemopoietic cells in migration through the endothelium. By …

Scanning Electron Microscopy Of The Microvascular System In The Inner Ear, Yoshiaki Nakai, Haruhiko Masutani, Hiromasa Cho

Scanning Electron Microscopy

In the present work, vessels casts in the inner ear of the rat and guinea pig, prepared by casting method using Mercox resin, were subjected to scanning electron microscopic examination and following results were obtained: 1) In adult guinea pig, numerous capillary nets were found in the following parts: stria vascularis, spiral ligament, spiral prominence, Corti's organ, spiral ganglion, plexus cochlearis, semicircular ampulla, saccule, utricle, and endolymphatic sac. These were consistent with functionally and morophologically important areas in the inner ear. 2) In the central side of the area with capillary nets, arterioles were found to run throughout, like a …

Scanning And Transmission Electron Microscopic Study Of Recovered Porcine Aortic Valved Conduits, D. J. Allen, I. H. Fentie, J. T. Davis, Angela Lineen

Scanning Electron Microscopy

Four explanted porcine aortic valved conduits were examined using scanning and transmission electron microscopy. Sources of obstruction such as neointima or "peel" and calcification were observed. In one sample the neointima was found to possess an unusually large expanse of squamous cells partially lining the luminal surface. This lining much resembled a normal endothelium, which is not an expected feature of neointima. Cells, presumably of host origin, were noted upon the leaflet surfaces. They did not seem as well organized as those found on the neointima. Calcification did not seem greatly advanced but was clearly apparent. Certain treatments proposed by …

Statoconia Formation In Molluscan Statocysts, Michael L. Wiederhold, Christine E. Sheridan, Nancy K. R. Smith

Scanning Electron Microscopy

The gravity sensors of all molluscs phylogenetically below the cephalopods are spherical organs called statocysts. The wall of the sphere contains mechanosensory cells whose sensory cilia project into the lumen of the cyst. The lumen is filled with fluid and dense "stones", the statoconia or statoliths, which sink under the influence of gravity to load, and stimulate, those receptor cells which are at the bottom. The statuconia of Aplysia californica are shown to be calcified about a lamellar arrangement of membranes. Similar lamellar membrane arrangements are seen within the receptor cells, and their possible role in the formation of the …

Cells From Xenopus Laevis Gastrulae Adhere To Fibronectin-Sepharose Beads And Other Lectin Coated Beads, Kurt E. Johnson, Michael H. Silver

Scanning Electron Microscopy

Cells from Xenopus laevis blastulae have a poorly developed ability to adhere to Sepharose beads covalently coupled to bovine plasma fibronectin (FN-beads). They do, however, have the ability to adhere to con A-beads and cytodex-1 and cytodex-3 beads. Beginning at the early gastrula stage, there is a progressively increasing ability of cells to adhere to FN-beads. Gastrula cells adhere to FN-beads by the formation of large ruffling lamellipodia. These cells can translocate on the surface of FN-beads; and when attached to both beads and the surrounding glass substratum of culture vessels, have the ability to move the beads extensively. Gastrula …

Adverse Effects Of Metals On The Alveolar Part Of The Lung, Anne Johansson, Per Camner

Scanning Electron Microscopy

Rabbits were exposed to low levels of metal dust or metal ions by inhalation for 1-8 months, 5 days/week and 6h/day. Following exposure lung tissue was examined by light and electron microscopy, the lung content of phospholipid was analyzed and the morphology and function of alveolar macrophages were investigated.

Metallic nickel dust as well as soluble nickel chloride produced accumulation of macrophages and laminated structures in alveoli and increased volume density of alveolar type II cells. The amount of phospholipids was elevated, mainly due to an increase in disaturated phosphatidylcholine. After one month exposure to metallic nickel dust or soluble …

Comparative Aspects Of Mammalian Spermiogenesis, Leif Plöen, Jean-Luc Courtens

Scanning Electron Microscopy

The testes of some different orders of eutherian mammals were examined by conventional electron microscopy with respect to their pattern of spermiogenesis. In addition, some of the testes were studied by cytochemical methods for demonstration of certain nuclear proteins and of glycoproteins in the acrosome and the plasma membrane of spermatids.

It was found that although the basic pattern of spermiogenesis was similar in all species studied, there were pronounced dissimilarities in the final shape of the spermatids. Differences were also observed in the timing of the differentiation of several organelles. The head of late spermatids and spermatozoa of Primates, …

Intracellular Structure Of The Outer Hair Cell Of The Organ Of Corti, Y. Harada, T. Sakai, N. Tagashira, M. Suzuki

Scanning Electron Microscopy

The intracellular structure of the outer hair cells of the normal guinea pig organ of Corti was investigated three dimensionally by scanning electron microscope. Freeze fracturing technique followed by maceration with a 0.1% OsO₄ solution (osmic maceration method) was used. Among the cell organelles, the endoplasmic reticulum (ER) showed the most interesting features, such as subsurface cisternae and lamellar bodies. The subsurface cisterna which formed a stratiform network covered the inner surface of the cell membrane and the stratiform structure disappeared at the infranuclear region. Variously shaped mitochondria (spherical, cylindrical and branched) were found on the innermost layer of …

Scanning Electron Microscopic Observation Of The Crista Ampullaris, Y. Harada, M. Takumida, N. Tagashira

Scanning Electron Microscopy

The crista ampullaris of the guinea pig and the bull frog were investigated by scanning electron microscopy. The crista ampullaris were freeze fractured or sheared followed by maceration with 0.1% OsO₄ solution. Following this, three-dimensional intracellular structures were observed. The mitochondria of the sensory cells varied in shape from globular to long and slender. Golgi apparatus and endoplasmic reticulum of the sensory cells were also demonstrated clearly. Nerve elements, nerve endings and synaptic structures were also observed stereoscopically.

Current Filament Formation In Gold Compensated Silicon Pin Diodes, H. Baumann, T. Pioch, H. Dahmen, D. Jäger

Scanning Electron Microscopy

In semiconducting materials with current controlled negative differential conductivity an inhomogeneous current density distribution can arise leading to a well-defined spatial pattern in the form of current filaments. Detailed experiments are performed on silicon pin diodes showing a pronounced multistability in the current voltage characteristics. By using the voltage contrast and the electron beam induced voltage (EBIV) methods in a SEM, it is confirmed that each jump in the current is accompanied with the formation or disappearance of a well defined transverse electrical structure between the two contacts as a result of a current filament. This non-uniform state of the …

Ultrastructural Studies Of Intercellular Contacts (Junctions) In Bone Marrow. A Review, Ferrell R. Campbell

Scanning Electron Microscopy

This paper reviews ultrastructural studies of the intercellular contacts or junctions between cells of the bone marrow. Studies using tannic acid and glutaraldehyde as a fixative have shown pentalaminar complexes between many types of cells in marrow of mice and chicks. These intercellular contacts occur between adjacent stromal cells, between stromal cells and developing blood cells and, in marrow of mice, between migrating blood cells and cells of the sinusoidal wall. Because of their location and widespread occurrence, it is believed these contacts may represent a type of adherent junction helping to maintain an orderly arrangement of blood cells and …

Ultrasonic Microdissection Of Immature Intermediate Human Placental Villi As Studied By Scanning Electron Microscopy, Gregory J. Highison, F. Donald Tibbitts

Scanning Electron Microscopy

The human placenta during the first 20 weeks of gestation undergoes rapid and extensive morphological changes. Near the end of this period, the most predominant type of villus present is the immature intermediate placental villus. In order to visualize this complex structure with scanning electron microscopy (SEM), we have developed a microdissection technique to expose tissue components of the placental villus while retaining its normal histological architecture. Placental villi were initially fixed in Karnovsky's fixative, buffered formalin, or 2% osmium tetroxide solution prior to exposure to connective tissue enzymes or detergents alone or in combination. Samples were dehydrated through 100% …

Scanning Electron Microscopy In The Evaluation Of Consolidation Treatments For Stone, A. E. Charola, R. J. Koestler

Scanning Electron Microscopy

The use of scanning electron microscopy (SEM) examination is shown to be an important tool in the evaluation of the effectiveness of consolidant treatments in stone. This implies the visualization of the attachment of the resin to the stone, the assessment of the degree of penetration and the distribution of the resin in the stone matrix. These factors can then be correlated with the chemical nature of the stone and the resin.

A sample preparation technique for limestone, based on acid etching of the surface, is described. This technique improves the visualization of the resin within the stone.

The Characteristic Structural Features Of The Blood Vessels Of The Lewis Lung Carcinoma (A Light Microscopic And Scanning Electron Microscopic Study), T. W. Grunt, A. Lametschwandtner, K. Karrer

Scanning Electron Microscopy

Vascular corrosion casts of Lewis lung carcinomas (LLC) grown subcutaneously in C57BL/6-mice are correlated with histological sections and with tumor tissue prepared for scanning electron microscopy (SEM). By making low, medium and high pressure cast preparations we studied the influence of perfusion and injection pressure on the resulting cast sample.

Three types of vascular proliferations are distinguishable in LLC: 1) Small globular outgrowths on sinusoidal dilated tumor capillaries, caused by proliferation of their endothelial cells. 2) New sprouts on surrounding host vessels, invading the small, still avascular implant. 3) Superficially located, centrifugally running sprouts in peripheral regions of large tumors. …

The Angioarchitecture Of The Lewis Lung Carcinoma In Laboratory Mice (A Light Microscopic And Scanning Electron Microscopic Study), T. W. Grunt, A. Lametschwandtner, K. Karrer, O. Staindl

Scanning Electron Microscopy

53 Lewis lung carcinomas implanted subcutaneously into C57BL/6-mice were examined. The animals were killed at various stages of tumor growth (TG) and prepared for histology and for scanning electron microscopy (critical-point-dried tissue; vascular corrosion casts). Prior to casting animals were rinsed using different perfusion pressures. Casting was done by manual injection of the resin, whereby different influx-rates were applied resulting in low, medium and high pressure preparations.

We discern 3 phases of tumor angiogenesis (TA) occurring during 4 stages of TG among which vasodilation establishes the first reaction of the host vascular system to a growing tumor implant. During this …

Changes In Absorptive Surfaces Of Rat Visceral Yolk Sac With Increasing Gestational Age, W. P. Jollie

Scanning Electron Microscopy

The free surface of the endodermal epithelial lining of the rat visceral yolk sac was examined by scanning electron microscopy at three stages of pregnancy, viz., 12, 17 and 22 days (birth typically occurring on the 23rd day). Additionally, by ultrasonic vibration of tissues that had been subjected to prolonged osmium fixation, the epithelium was removed and such microdissected membranes similarly were examined.

With increasing gestational age the free surface of the epithelium. underwent a relative increase in absorptive area by three mechanisms: formation of increasingly complex villous projections of the visceral yolk sac as a whole, a doming of …

Application Of Scanning Electron Microscopy To The Study Of Shark Dermal Denticles, G. Dingerkus, R. J. Koestler

Scanning Electron Microscopy

Clear, high resolution scanning electron micrographs of shark dermal denticles are essential to allow the study of their morphology and micro-relief. Various techniques were tried to remove mucus and adventitious debris, including KOH, trypsin enzyme, and ultrasonication. In most species examined the best results were obtained with enzyme treatment followed by ultrasonication. For scanning electron microscopic examination it was found that 15 nm gold coating, or more, and 10 kV, or less, had to be employed to reduce charging of the denticles.