Biology Commons^™

Scanning Electron Microscopy Of The Lateral Ventricle Of The Pigeon Brain, P. Mestres, K. Rascher, J. D. Delius

Scanning Electron Microscopy

Adult pigeons of both sexes were used for this study. Depending upon the distribution of various surface profiles, for example cilia, microvilli and blebs, ependymal areas with differing surface patterns were distinguished in the lateral ventricle. The topographical locations of these areas with respect to the underlying forebrain nuclei were determined in accord with the atlas of Karten and Hodos (1967). The medial surface (A) of the ventricle was much more densely ciliated than the lateral surface (B). There did not appear to be any correlation between a given surface pattern and a specific type of underlying nervous tissue. Comparison …

Characterization Of Carbonaceous Materials By Correlated Electron And Optical Microscopy And Raman Microspectroscopy, C. Beny-Bassez, J. N. Rouzaud

Scanning Electron Microscopy

Carbonaceous materials differ according to their chemical composition (types of heteroatoms), their structure and their microtexture. So, it is interesting to find methods for characterizing them. We choose to correlate data from Raman microspectroscopy, optical microscopy and transmission electron microscopy. First, we use both graphitizable or non-graphitizable reference carbon series of simple chemical composition in order to follow the structural transformation of the carbonaceous materials according to the evolution of these data throughout heat-treatment of these samples. Then, the coals of different ranks are studied.

The Raman results are correlated with those from electron microscopy, particularly by plotting, for the …

Advances In Non-Contact Thermal-Wave Imaging With Infrared Detection, F. H. Dacol, H. Ermert, R. L. Melcher

Scanning Electron Microscopy

We are making further advances in non-destructive and non-contact thermal imaging with infrared detection. We employ a chopped and scanned electron beam as heat source, a cooled HgCdTe infrared detector as temperature sensor, and digital processing of the measured temperature pattern for display and storage. The results give a convincing, high contrast image of subsurface structures.

Scanning Electron Microscopy Methodology For Study Of The Pathophysiology Of Calcification In Bioprosthetic Heart Valves, Alan C. Nelson, Frederick J. Schoen, Robert J. Levy

Scanning Electron Microscopy

Scanning electron microscope (SEM) morphologic analysis combined with energy dispersive characteristic X-ray (EDX) microprobe analysis provides insight into the mechanisms associated with disease-related crystal formation in biological materials. SEM and EDX were employed in analyzing specimens which were embedded in standard fashion in glycolmethacrylate (JB-4). The specimen surfaces under electron microscope investigation resulted from microtomy used in the preparation of reference light microscope histological sections; thus histology served as a direct reference for the SEM and EDX analyses.

The particular application of these methods was in the study of bioprosthetic heart valve calcification, largely responsible for clinical failure of these …

Detection System For Scanning Electron Microscope, J. Hejna, Z. Radzimski, A. Buczkowski

Scanning Electron Microscopy

The kind of information and the quality of the backscattered electron (BSE) images depend upon numerous features of the detector. Therefore, various types of detectors should be used simultaneously to obtain as much of information as possible. The detection system presented here contains a large area semiconductor detector and a BSE to secondary electrons (SE) converter system. These two different kinds of detectors give different BSE images. After subtracting the signal of a semiconductor detector from that of a converter system, an image with good topography and reduced material contrast can be achieved.

Ultrasonic Microdissection Of Rat Cerebellum For Scanning Electron Microscopy, C. E. Arnett Iii, F. N. Low

Scanning Electron Microscopy

The cerebelli of rats were initially fixed with aldehydes (modified Karnovsky's fixative; 503 mOsM/L) by cardiac perfusion. Blocks of tissue were razor-cut, usually longitudinal to folia, and immersed in the same fluid for 2-4 hours. Three separate methods of treatment followed: (1) immersion in 1% aqueous boric acid, or (2) in 2% phosphate buffered OsO₄ followed by boric acid or (3) in an 8/2 mixture of boric acid and OsO₄. After 18-48 hours immersion the blocks were dehydrated in ascending grades of acetone. They were then exposed to ultrasound in 100% acetone at frequencies of 80 kHz …

Use Of Scanning Electron Microscopy To Study Structural-Functional Relationships In Normal And Diseased Platelets, J. C. Mattson

Scanning Electron Microscopy

This paper reviews the contribution of scanning electron microscopy (SEM) to our understanding of platelet physiology and pathology. Observations of platelet shape changes which accompany activation and the ability to visualize and analyze platelet aggregation and adhesion in three dimensions make this experimental medium an important tool in the evaluation of healthy and diseased platelets. While SEM adds a valuable third dimension to the study of morphology and ultrastructure, its greatest contribution is realized when studies are correlated directly with light and/or transmission electron microscopic observations and with studies of functional capacity.

Morphological Study Of The Anodic-Oxide And Hydrated-Oxide Films On Pure Aluminium, S. M. El-Mashri

Scanning Electron Microscopy

A high resolution scanning transmission electron microscope (STEM), operated in the SEM mode, has been used to examine the morphology of the oxide anodically formed on a surface of pure aluminium, using different electrolyte solutions (tartaric, oxalic, boric, phosphoric and chromic acids). The microstructural changes of these films following their hydration in hot water showed degradation of the oxide and conversion to an oxy-hydroxide phase (pseudo-boehmite). These observations are in agreement with previous EXAFS measurements of the Al-O bondlength which indicated the formation of crystalline boehmite (AlOOH). Observation of the oxide and oxy-hydroxide derived from anodisation in phosphoric acid electrolyte …

Some Considerations Of The Ultimate Spatial Resolution Achievable In Scanning Transmission Electron Microscopy, Anthony J. Garratt-Reed

Scanning Electron Microscopy

The fundamental limitations on spatial resolution of X-ray microanalysis in the scanning transmission electron microscope are set by the interrelationships between the gun brightness, operating voltage, probe convergence angle, size and current, specimen thickness, beam broadening, the probability of characteristic and Bremsstrahlung X-ray production and the statistics of the X-ray spectrum. Manipulation of expressions describing these interrelationships leads to equations predicting the optimum probe size and specimen thickness for the best achievable spatial resolution (defined as the diameter of a cylinder containing 90% of the X-ray production) in microscopes fitted with different electron sources and operating at different voltages in …

Recent Advances In Laser Microprobe Mass Analysis (Lamma) Of Inner Ear Tissue, A. Meyer Zum Gottesberge-Orsulakova, R. Kaufmann

Scanning Electron Microscopy

Maintenance of ionic gradients within the various fluids compartments of the inner ear requires transport active cellular systems at different locations. LAMMA analysis is ideally suited for detection of ions in microquantity on cellular levels overcoming many technical difficulties. The present paper summarizes the results of microprobe analysis obtained with laser induced mass spectrometry (LAMMA) supplemented by X-ray microprobe analysis of epithelial cell layers adjacent to the endolymphatic space (a) in the cochlear duct, (b) in the vestibular organ and (c) in the endolymphatic sac. The possible role of inner ear as well as ocular melanin in the mechanisms of …

The Ependyma Of The Cat Central Canal, With Particular Reference To Its Mitochondria-Containing Bulbs, K. Rascher, K. H. Booz, A. C. Nacimiento, E. Donauer

Scanning Electron Microscopy

The ultrastructure of the ependyma in the central canal of adult cats was examined in both the scanning and the transmission electron microscopes (SEM and TEM).

The same morphological details were seen in the ependyma of the central canal as have so frequently been described in the ependyma of the brain ventricular system, for example bundles of cilia, single cilia, microvilli and occasional small cytoplasmic protrusions. The supraependymal cells and supraependymal nerve fibers found in the central canal also resembled those seen in the ventricular system.

The most striking feature of the canal ependyma were the large, spherical bodies containing …

Scanning And Transmission Electron Microscopic Studies On The Oviducts Of Pekin Ducks Fed Methyl Mercury Containing Diets, A. Balachandran, M. K. Bhatnagar, H. D. Geissinger

Scanning Electron Microscopy

This study was undertaken to examine the effects of varying levels of methyl mercury (MeHg) on the ultrastructure of the surface epithelium of the oviduct of ducks. Accordingly, Pekin ducks were maintained on feed containing varying doses of (0.0; 0.5; 5.0; 15.0 ppm) of MeHg (Group I - control to IV) for 12 weeks and sacrificed. Tissue from the magnum and the shell gland regions of the oviduct was processed for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the primary and secondary folds of these regions of the oviducts of the control and 0.5 …

Microcharacterization Of Fluid Inclusions In Minerals By Raman Microprobe, J. C. Touray, C. Beny-Bassez, J. Dubessy, N. Guilhaumou

Scanning Electron Microscopy

Fluids trapped in inclusions in minerals are micro-amounts of ore-forming media composed of water, dissolved salts, gases and sometimes liquefied gases, liquid, hydrocarbons and solids. The aim of this paper is to summarize the contribution of the Raman scattering microspectrometry to the knowledge of fluid inclusions. After a review of the composition of fluid inclusions and a short presentation of microthermometrical investigations, a description of the Raman microprobe is given. Applications are reviewed; identification of ionic species dissolved in aqueous phase, characterization of gases of C-O-H-N-S system, identification of solids and non aqueous liquids. The complementary characteristics of Raman microanalysis …

Calcium Oxalate Crystal Production In Two Members Of The Mucorales, M. D. Powell, H. J. Arnott

Scanning Electron Microscopy

Calcium oxalate crystals are found in association with the sporangia of Mucor hiemalis and Rhizopus oryzae. Crystals observed in each species vary in morphology from simple crystals consisting of single spines in M. hiemalis to complex crystals with twin spines, sometimes three-parted, on a common base in R. oryzae. The early development of the crystals is similar in both species with a layer of the cell wall covering in the initial crystals. The spines of M. hiemalis rapidly emerge while the crystals of R. oryzae appear to remain covered with a layer of outer wall material. The crystals …

Parameters Of Growth In The Embryonic And Neonatal Chick Basilar Papilla, Douglas A. Cotanche, Kathleen K. Sulik

Scanning Electron Microscopy

The growth of the basilar papilla in the chick cochlear duct was studied utilizing light, scanning, and transmission electron microscopy. The ages of the cochleae investigated ranged from embryonic day 6 to post-hatching day 7. The changes in the length and width of the basilar papilla as well as the establishment of its spatula-like shape were correlated with the maturation of the hair cells' apical surfaces and the changes in the cellular organization of the sensory epithelium. The histological reorganization of the distal hair cell nuclei was concomitant with the broadening of the distal region of the basilar papilla and …

Energy Dispersive X-Ray Analysis Of Ocean Ferromanganese Crusts Using Conventional Zaf Corrections, R. F. Commeau, J. A. Commeau, F. W. Brown, F. T. Manheim

Scanning Electron Microscopy

Ocean ferromanganese crusts are composed of interlayered phases of manganese oxide, iron oxide and oxyhydroxide, calcium carbonate/phosphate, silica, and alumino-silicates. These interlayers are so thin and fine-grained that each phase could not be isolated under the beam of a scanning electron microscope for quantitative x-ray microanalysis. A test was conducted to determine if the grain size of the phases was small enough to allow conventional ZAF techniques to be used without serious errors in the results. A "synthetic" ferromanganese crust was prepared by pelletization of a 1:1 mix of two fine-grained (<5 >micrometer) components. The mean of the energy dispersive …

An Ultrastructural Analysis Of The Physical Organization Of Collagenous (Type I) Matrices: One Determinant Of Urothelium Maintenance In Vitro, G. M. Hodges, C. Rowlatt, A. R. Howlett, L. K. Trejdosiewicz

Scanning Electron Microscopy

Collagenous matrices, used as cell culture substrata, can be prepared from different collagen types in a variety of forms using a range of polymerization procedures. Type I collagen has been most frequently used either as dried collagen films or hydrated collagen gels. Sheets of isolated bladder urothelium, when plated onto such matrices prepared from type I collagen by different polymerization methods (eg. air-drying; NaOH; NaCl; NH₃; or NH₃ followed by glutaraldehyde crosslinking) demonstrate the capability of urothelial cells to attach to a variety of differently prepared matrices irrespective of polymerization procedure. In contrast, both cell proliferation and …

The Influence Of Different Cryopreparations On The Distribution Of Ions In Bullfrog Myocard Cells, R. Meyer, M. Schmitz, K. Zierold

Scanning Electron Microscopy

Bullfrog heart muscle trabecula are shock-frozen in liquid propane cooled by liquid nitrogen and then processed for X-ray microanalysis in two different ways: 1. Freeze-drying followed by vacuum embedding. 2. Cryoultramicrotomy and freeze-drying.

Stained sections of freeze-dried, embedded tissue exhibit detailed ultrastructure, but are useless for X-ray microanalysis. Unstained, dry cut plastic-sections are suitable for X-ray microanalysis, but the ultrastructure appears faint. Higher electron optical contrast and peak-to-background ratio of X-ray spectra are generally obtained in freeze-dried cryosections. Both preparation methods show that the X-ray spectra are influenced by the quality of cryofixation. The phosphorus/potassium ratio in nuclei increases with …

Advances In Electron-Beam-Induced-Current Analysis Of Integrated Circuits, J. D. Schick

Scanning Electron Microscopy

Electron-beam-induced-current (EBIC) analysis of integrated circuits and of individual semiconductor devices has become an essential technique for semiconductor device characterization as well as for failure analysis and diagnostics. This tutorial is an update of the paper presented in SEM/1981/I on the same topic and discusses advances and new trends in the applications of EBIC in recent months. Examples of EBIC measurements on high density chips, ion-implanted junctions, and shallow diffusions in thin epitaxial layers are given. Time resolved EBIC (TREBIC) is also explained and new digital readout techniques, including computer-aided data analysis, are described as they refer to detailed analyses …

Endometrium Cell Surface Abnormalities In The Syrian Hamster As A Result Of In Utero Exposure To Diethylstilbestrol, J. Gilloteaux, A. W. Steggles

Scanning Electron Microscopy

Scanning electron microscopy (SEM) was used to observe changes in the hamster endometrium cell surface following in utero pre- and/or postnatal exposure to diethylstilbestrol (DES). Some of the changes in cell surfaces are associated with alterations in cell sizes and shapes (from columnar to cuboidal and/or squamous) and in microvilli and mucous secretion. In all cases, DES treated uteri show mucosal cell surface pleomorphism, apocrine secretion and cystic accumulation of secretory material. Microvillous pleomorphism and peculiar linkages attaching one microvillus to others were investigated. Although the function and nature of such linkages is unclear, their presence seems to be more …

The Role Of The Vessels In The Growth Plate: Morphological Examination, K. Draenert, Y. Draenert

Scanning Electron Microscopy

Combined methods of light microscopy to present ossification zones by means of fluorochrome dyes make it possible to explain the contradicting presentations of the vascular system of the growth plate in the literature. The vascular system was casted with methacrylates which can be presented in the scanning electron microscope 3-dimensionally together with the trabeculae as a result of their resistance in the electron beam.

The 3-dimensional presentation in the electron microscope allows a clear distinction between the various vascular sections in the arterial flow system. In the microcorrosion casts the vessels of the epiphyseal side of the growth plate can …

Interactive Image Processing For Electron Microscopy: Matching Hardware With Software, W. O. Saxton

Scanning Electron Microscopy

The image processing techniques used 'a posteriori' to extract information from electron micrographs are surveyed, including particularly image averaging, selective averaging, 3-D reconstruction, and high resolution focal series restoration; recent developments in online image pick up and control have led to fully automatic focussing, stigmating and alignment by a frame store system equipped with a real time correlator board. The diversity of the techniques encountered calls for large integrated program systems with flexible command languages; however, a dilemma exists between providing the user with convenient control of special hardware facilities such as frame stores and array processors, and preventing the …

Optics Of Wide Electron Beam Focusing, Zhou Li-Wei

Scanning Electron Microscopy

In the present paper, we have further studied an approach to the theoretical treatment of wide electron beam focusing, based on the application of the theory of focusing fields with arbitrary curved optical axis, considering the initial condition emitted from the cathode surface. It is assumed that the magnetic field vector B will be used instead of the magnetic scalar potential Ω and the electrostatic potential 𝞅 and the magnetic field vector B are known functions either by computation or experimentally in the laboratory system of coordinates. The new approach to the mathematical treatment appears to be a useful method …

The Application Of The Alternating Procedure Of H.A. Schwarz For Computing Three-Dimensional Electrostatic Fields In Electron-Optical Systems, Christoph H. Schaefer

Scanning Electron Microscopy

The numerical solution of three-dimensional electrostatic field problems in electron-optical devices with complicated boundaries requires the use of very large and fast computers. A numerical counterpart of the Alternating Procedure by H. A. Schwarz (SAP) makes efficient use of both storage space and time available on the computer and therefore represents a useful new method in this context. In this method. the domain of solution is decomposed into independent subdomains where the appropriate individual methods of solution may be chosen. Correspondingly. the original boundary value problem is decomposed into a sequence of boundary value problems in these subdomains. SAP requires …

Constrained Optimization Design Of An Electron Optical System, Chang-Xin Gu, Li-Ying Shan

Scanning Electron Microscopy

An electron optical system can be optimized using the "simplex method" or "complex method". By these methods, the final structure of an electron optical system, for example, an extended field lens (EFL), can be searched with a criterion of minimum objective parameter (in the present case, the coefficient of spherical aberration). Because there is no constraint in the simplex method, the constrained optimization method (the complex method) described in this paper is better than the simplex method in the design of electron optical systems. In the simplex method as well as the complex method, it is not necessary to know …

Study Of Space Charge Limitation Of Thermionic Cathodes In Triode Guns, A. Delâge, P. B. Sewell

Scanning Electron Microscopy

A computer program has been developed to compute the emission of cathodes from the fully space charge limited diode equation. The emission of four different gun arrangements with thermionic cathodes of the type used in electron microscopes is investigated. Microflat cathodes with a small (≤50𝜇m in diameter) fixed emitting area show several advantages for high brightness possibilities whereas other types of cathodes for which the emitting area increases with the brightness are usually limited by too great a total emission.

Thermionic Emission Studies Of Micro-Flat Single Crystal Lanthanum Hexaboride Cathodes, P. B. Sewell, A. Delâge

Scanning Electron Microscopy

A new type of high brightness thermionic cathode has been developed. The cathode utilises emission from a small flat surface (generally less than 50 μm diameter) prepared parallel to a specific crystal plane on a single crystal of Lanthanum Hexaboride. Emission from the rest of the single crystal is suppressed by the use of a high work function coating of pyrolytic graphite. When used in a conventional triode gun, the maximum total electron emission is controlled by the area of the micro-flat, the work function and the temperature of the emitter. The Wehnelt potential serves a minor role in controlling …

Microchannel Plates As Specialized Scanning Electron Microscopy Detectors, P. E. Russell

Scanning Electron Microscopy

The need for a specialized detector for low beam voltage and low beam current applications has led to the investigation of a microchannel plate detector for SEM. The application requirements are described in detail, with the case of integrated circuit metrology used as an example. The microchannel plate (MCP) detector has proven to meet almost all of the design objectives of a low voltage metrology SEM detector. The symmetry of the detector and the ability to mount it directly to the final pole piece are among the most important features.

Electrostatic And Magnetic Imaging Without Image Rotation, Zhou Li-Wei, Ni Guo-Qiang, Fang Er-Lun

Scanning Electron Microscopy

A method is discussed for designing electrostatic and magnetic imaging systems without image rotation. Tsukkerman's condition for an imaging system free of rotation does not appear to be applicable to practical designs. We have modified his theory to obtain two other conditions for the normalized axial electric potential V(z), the normalized axial magnetic induction G(z), and a lens strength parameter 𝞴 which can be interpreted as an eigen-value. Some analytical examples and numerical results are given.

The Influence Of Sample And Detector Angles Upon Auger Electron Signal, Robert L. Gerlach

Scanning Electron Microscopy

The effects of the sample to incident electron beam angle and of the detector. angle on the Auger electron signal are important for quantitative Auger analysis, particularly for Auger mapping and line scans. A first approximation, single scattering, mean free path model is employed to simulate the Auger signal resulting from a range of sample and detector angles. The model is single scattering in the sense that the excitation path is taken to be a straight line into the solid. A second model approximates multiple scattering by a normal distribution of ionizing flux angles about the incident beam direction.

Since …