Biology Commons^™

Ranking Corrosion Efficiency: A Latin Square Study On Rat Lung Microvascular Corrosion Casts, Dean E. Schraufnagel

Scanning Microscopy

Scanning electron microscopy of corrosion casts is an important tool for the study of microvascular structure but few systematic studies on methods of specimen preparation have been reported. This study sought to determine the relative importance of factors involved in corrosion. It compared potassium hydroxide, sodium hydroxide and water as major corrosive agents. It tested the size of the tissue sample, and the use of prealkali autolysis, detergent, and proteolytic enzymes in a Latin square designed study. The main findings were that sodium and potassium hydroxide were better than water (P < 0.0001) and the longer the corrosion time the better corroded the samples were (P < 0.0001 ). Although not a controlled factor, higher room temperature was also associated with better corrosion. The use of proteolytic enzymes, detergent, and warm tap water alone before the alkali treatment did not significantly improve the corrosion in this study, although this does not preclude an effect with another experimental design.

Scanning Near Field Optical Microscopy (Snom) In Reflection Or Scanning Optical Tunneling Microscopy (Sotm), U. Ch. Fischer, U. T. Dürig, D. W. Pohl

Scanning Microscopy

The recent exploitation of near field optics opened a new branch of light microscopy beyond the diffraction limit. With scanning near field optical microscopy a lateral resolution of 20 and 50 nm was obtained in transmission and reflection, respectively. In a novel optical tunneling mode, also the topography of pure phase objects has been imaged at a resolution of 50 nm laterally and 1 nm vertically.

Modular Detector System For Scanning Transmission Electron Microscope, A. V. Jones, M. Haider

Scanning Microscopy

This paper describes a multiple detector system based on a high-dispersion highly-corrected spectrometer close-coupled to a high-excitation objective lens. The design enables all post-specimen detectors (including the elastic dark-field detector) to be transferred to the post-spectrometer region.

This in turn makes possible the simultaneous acquisition of filtered bright-field, elastic dark-field and inelastic images.

The associated data acquisition system has provision for up to four simultaneous inputs and is based on a 32-bit microprocessor with 2 Mbytes of memory and 85 Mbytes of local disk storage. Images can be archived locally (cassette tape) or transferred via Ethernet to the laboratory central …

Determination Of Protein, R. Reichelt, A. Engel

Scanning Microscopy

Elastic and inelastic dark-field micrographs simultaneously recorded by the scanning transmission electron microscope (STEM) provide structural and quantitative chemical information at a spatial resolution of some nanometers. Simultaneous acquisition is essential as it warrants: (i) the geometrical identity of picture elements (pixels) in these micrographs, and (ii) the identity of recording conditions (focus, electron dose) for the elastic and inelastic images. Suitable off-line processing of such multichannel images allows the concentration of protein or nucleic acid within embedding material to be evaluated. In addition, location and number of chemical elements such as phosphorus can be determined. Theoretical sensitivity is a …

Scanning Electron Microscopy In The Study Of Campylobacter Pylori Associated Gastritis, F. Bonvicini, P. Versura, S. Pretolani, G. Gasbarrini, R. Laschi

Scanning Microscopy

The close association between Campylobacter pylori (CP), gastritis and peptic ulcer is now well established. Moreover increasing evidence has been collected of a major etiological role of CP in type B chronic gastritis. For this reason, searching for CP is essential in all patients with upper gastrointestinal symptoms.

Scanning electron microscopy (SEM) is a most reliable technique for studying the distribution of microorganisms and their relationship to the gastric mucosal surface.

The aim of this paper is to compare SEM to other routine methods of detection for CP, such as Giemsa staining on histological sections and Urease Microtiter Test (MT) …

Scanning Electron Microscopy Of Chondritic Meteorites: Evidence For Condensation And Aggregation Processes During The Birth Of The Solar System, Glenn J. Macpherson, Jeffrey N. Grossman

Scanning Microscopy

Carbonaceous chondrite meteorites preserve evidence of how the solar system formed and evolved through its earliest stages. Extracting these clues from small and very fine grained (a few tens of μm and smaller in many cases) meteorite components has required extensive use of micro beam techniques-scanning electron microscopy (SEM), electron and ion microprobe. Correlated studies have allowed textural, major and trace element and isotopic data to be gathered on the same precious microsamples. The best method for examining textures in these meteorites is scanning electron microscopy of flat polished sections using compositional back-scattered electron imaging.

X-Ray Microanalysis Of Mammalian Salivary Glands, Godfried M. Roomans, R. Margareta Müller, Samuel Sagström, Gun-Britt Sagulin, Susan M. Scarlett, Joanna Wroblewski, Maria Albertsson

Scanning Microscopy

X-ray microanalysis was used to study the elemental composition of major salivary glands in rat and man. The elemental composition of the acinar cells is influenced by a variety of factors. Stimulation of fluid secretion by cholinergic, α-adrenergic or peptidergic agonists leads to a sustained increase of the Na/K ratio. The elemental composition and ultrastructure of the acinar cells of rat submandibular gland, as well as flow rate and composition of pilocarpinestimulated submandibular saliva are significantly affected by thyroxine, but less by the synthetic glucocorticoid dexamethasone. Hypercalcemia (induced by chronic vitamin D treatment) as well as hypocalcemia (induced by calcitonin) …

Determination Of Sulfur And Iron Valence By Microprobe, H. Kucha, R. Wouters, O. Arkens

Scanning Microscopy

SKα, SKβ and FeKβ valence related wavelength changes are large enough to be measured with microprobe spectrometers. The relative difference between S^2- and S⁶⁺ is measured as 1.27 eV for the SKα line and 1.66 eV for the SKβ line. This SKα and SKβ peak shift is function of the valence. Accurate microprobe measurement of the peak shift allows the determination of the sulfur valence in a microarea. The relative difference between Fe²⁺ and Fe³⁺ for the FeKβ line is 0.94 eV. Considering the achieved accuracy of measurements, this peak can only be used for an …

Prospects For Photo Electron Spectroscopy In A Scanning Transmission Electron Microscope, F. J. Pijper, A. J. Bleeker, R. J. Endert, P. Kruit

Scanning Microscopy

High spatial resolution microanalysis in scanning transmission electron microscopes is most easily performed when the specimen is inside a magnetic immersion objective lens. Recently a technique has been developed to perform spectroscopy of electrons that originate in this magnetic field. A very special form of photo electron spectroscopy is then possible for thin specimens in the microscope. An energy loss ΔE of a primary electron has the same physical effect as the absorption of a photon of energy ΔE. A coincidence measurement between energy loss electrons and the emitted electrons is expected to give a so called coincidence electron spectrum, …

'Spot The Difference': Finding Small Differences Between Closely Similar Images, A. A. Mills

Scanning Microscopy

Small differences between two complex and closely-similar photographs may be located by viewing the uniformly illuminated pair with a stereoscope. Provided the observer possesses normal stereoscopic vision, any non-common elements will appear to stand above the general picture plane provided by the fused common background. It is emphasised that the images being examined are not a conventional stereo-pair, although the left- or right-eye member of such a pair may be so compared with its counterpart in a subsequent stereopair. This stereoscopic technique was found preferable to the alternative 'blink' method for most scanning microscope images, although it is advantageous to …

Architecture Of The Medial Smooth Muscle Of The Arterial Vessels In The Normal Human Brain: A Scanning Electron-Microscopic Study, Toshitaka Shiraishi, Saburo Sakaki, Yasuo Uehara

Scanning Microscopy

The architecture of the medial smooth muscle of arterial vessels in normal human brains was investigated using scanning electron microscopy. We could divide the arterial vessels into four subdivisions according to the number of the circular muscle cells. The arteries ( > 100 μm in diameter) had 4-20 layers of circular smooth muscle cells; individual circular muscle cells were spindle-shaped and occasionally had branches at their ends. Multidirectional muscle cells were observed in the medio-adventitial border only at the branching sites in large arteries (>300 μm), but at both branching and non-branching sites in the small arteries (100-300 μm). The …

Analyses Of Dental Pulp In Restored Teeth, D. L. Lentz, J. T. Buchanan, D. R. Basinger

Scanning Microscopy

Restored teeth were extracted from test animals at four time intervals (1 hour, 1 day, 1 week, and 3 months) following amalgam insertion. Extracted teeth were frozen in liquid nitrogen, cryo-fractured so as to expose the pulps and then freeze-dried. Pulps were analyzed for mercury content by energy dispersive spectrometry (EDS) and atomic absorption spectrophotometry (AAS). Mercury levels appeared below the detection limits of EDS but could be detected by AAS which showed the highest readings seven days after amalgam insertion.

The Response Phase - The First Six Hours After Acute Airway Injury By So2 Inhalation: An In Vivo And In Vitro Study, W. C. Hulbert, S. F. P. Man, M. K. Rosychuk, G. Braybrook, J. G. Mehta

Scanning Microscopy

We have identified an airway epithelial response following acute injury that cannot be termed 'repair' or regeneration. It precedes these well characterized events and it is termed the 'response phase'. We tested the hypothesis that for the first 6 h following acute injury to the tracheal mucosa, the initial cellular events of the response phase will continue as in vivo even if the tissue is maintained in vitro in an Ussing chamber. The tracheal mucosa of anesthetized, intubated mongrel dogs was injured by the inhalation of SO₂ 500 ppm for 1 h (7 dogs); controls (3 dogs) breathed filtered, …

X-Ray Microanalysis Of Calcium Containing Organelles In Resin Embedded Tissue, G. Nicaise, I. Gillot, A. K. Julliard, E. Keicher, S. Blaineau, J. Amsellem, J. C. Meyran, M. L. Hernandez-Nicaise, B. Ciapa, C. Gleyzal

Scanning Microscopy

The localization of calcium in cell organelles at the electron microscope level is often achieved through cytochemical techniques, and verified by X-ray microanalysis. Various methods have been used to cytochemically detect calcium or calcium-binding sites : calcium loading, calcium substitution by strontium, barium, or even lead, and calcium precipitation by oxalate, phosphate, fluoride, or pyroantimonate. Their results may have heuristic value, particularly in preliminary studies of poorly known cell types. A complementary and more physiological approach is offered by quantitative measurement of the total calcium content of organelles after cryofixation.

Resin embedding is less demanding than cryomicrotomy and gives better …

Design And Applications Of In-Situ Differential Scanning Electron Microscopy, A. Sicignano, M. Vaez Iravani

Scanning Microscopy

Contrast enhancement in the scanning electron microscope (SEM) is usually achieved by either of the two techniques of black level suppression, and differential imaging. This paper is mainly concerned with the latter method. Differential imaging of SEM images is commonly accomplished by either using a selective electronic filtering circuit (time sensitive) on the video signals, or the post processing of a collected digitized image (application of special kernel operatives). A technique is described that is capable of generating true in-situ SEM differential video signals of local sample features. Characteristics of this method are enhanced sample feature-boundary sensitivity, suppression of large …

Mechanism Of Hydrolysis Of Octacalcium Phosphate, B. B. Tomazic, M. S. Tung, T. M. Gregory, W. E. Brown

Scanning Microscopy

The chemical and structural properties of hydrolyzed octacalcium phosphate (OCP) appear to be of high relevance to tooth, bone and pathological bioapatites. Hydrolysis of synthetic well-crystallized OCP was studied at constant pH by using the pH stat method over the 6.1 to 8.6 range at 50°C and to a lesser extent at 37°C. Hydrolytic transformation proceeds according to thermodynamic requirements except for some retardation at the highest pH value as a consequence of decreased solubility of OCP which may be rate determining. The product of hydrolysis, OCP-hydrolyzate (OCPH), was characterized by chemical analysis, scanning electron microscopy, x-ray diffraction, electron microprobe …

Sodium Lauryl Sulfate Enhances Nickel Penetration Through Guinea-Pig Skin. Studies With Energy Dispersive X-Ray Microanalysis, Magnus Lindberg, Samuel Sagström, Godfried M. Roomans, Bo Forslind

Scanning Microscopy

The effect of sodium lauryl sulphate (SLS), a common ingredient of detergents, on the penetration of nickel through the stratum corneum in the guinea-pig skin model was studied with energy dispersive X-ray microanalysis ( EDX) to evaluate the barrier-damaging properties of this common detergent. The EDX technique allows a simultaneous determination of physiologically important elements, e.g., Na. Mg, P, Cl, K, Ca and S in addition to Ni at each point of measurement in epidermal cell strata. Our results show that SLS reduces the barrier function to Ni-ion penetration of the stratum corneum. In addition we have shown that EDX …

Scanning Electron Microscope And X-Ray Diffraction Investigations Of Mudrock Fabrics, Textures And Mineralogy, J. M. Huggett

Scanning Microscopy

Mudstones from a broad range of depositional environments have been investigated to determine whether fabric, texture or mineralogy may (1) be used to identify the environment of deposition and (2) be correlated with poroperm. The diversity of fabrics and textures reflects features of the detrital mudstone composition, compaction and diagenesis, rather than environment of deposition. Preferred orientation has been disturbed by bioturbation and growth of post-compactional authigenic minerals; these factors have reduced to nil any correlation which may have existed between fabric, measured as the illite orientation ratio (O/R) and environment of deposition.

It is mineralogy rather than fabric or …

Preparation Of Dipteran Larvae For Scanning Electron Microscopy With Special Reference To Myiasigen Dipteran Species, I. Ruiz-Martinez, M. D. Soler-Cruz, R. Benitez-Rodriguez, M. Diaz Lopez, J. M. Perez-Jimenez

Scanning Microscopy

Although controversy exists concerning the role of chemical fixatives in scanning electron microscopy (SEM) studies of Dipteran larvae, we have observed that filtered 10% formaldehyde solution gives excellent results as a preservative. After immersing in vivo in formaldehyde, the larvae material is preserved for prolonged periods (up to 8 months), before examination with SEM. As a fixative, formaldehyde preserves the structure of the larval cuticle and produces no visible artifacts. Moreover, postfixation is not necessary.

Due to pecularities of the way of life of Wohlfahrtia magnifica (principally the accumulations of necrotic tissue, purulent particles, and other types of substances that …

The Vascular System Of Xenotransplanted Tumors -Scanning Electron And Light Microscopic Studies-, M. A. Konerding, F. Steinberg, V. Budach

Scanning Microscopy

A widely used model for investigating basic tumor characteristics and different treatment modalities preclinically is the immune-deficient, athymic nude mouse. This model offers many morphological parallelisms to the clinical situation.

The aim of this study is to demonstrate the vascularization pattern of xenotransplanted human melanomas and sarcomas using different methods. Xenotransplanted tumors of 62 congenital thymusaplastic nude mice were examined ultrastructurally and topographically after corrosion cast and tissue preparation. Quantitative measurements of tumors injected with India ink were carried out to obtain comparable information on the vascular densities in the tumors.

Quantitative measurements showed that there is no zonal, topographic …

Altered Fungal Morphogenesis During Early Stages Of Ectomycorrhiza Formation In Eucalyptus Pilularis, P. F. Jacobs, R. L. Peterson, H. B. Massicotte

Scanning Microscopy

Scanning electron microscopy (SEM) of Eucalyptus pilularis roots inoculated with Pisolithus tinctorius, under controlled conditions, revealed altered morphogenesis of fungal hyphae in contact with the root surface. These changes occurred prior to the formation of a full fungal mantle and resulted in the formation of a compact fungal layer as a consequence of fusion of proliferating, branching hyphae. Although similar growth patterns have been observed in the inner mantle of fully developed ectomycorrhizae using contrast interference microscopy, this is the first time this feature has been observed during early mantle formation using SEM. Changes in fungal morphology during early …

Quantitative Microanalysis Of Nitrogen Distribution In Carpospores Of Gracilaria Secundata With Scanning Auger Microscopy, Åke Lignell, Rein Kalm, Godfried M. Roomans, Angelica Von Hofsten, Olof Vingsbo

Scanning Microscopy

Quantitative microanalysis has been performed with a JAMP 10 Scanning Auger Microscope at 0.5 μm spot size, on carpospores of Gracilaria secundata Harv.. Samples were fixed in glutaraldehyde and osmium tetroxide and embedded in plastic material. Thin sections were placed on solid copper discs. the surfaces of which had been smoothed by electropolishing.

Quantification of the nitrogen content was performed using a standard with known content of nitrogen.

Nitrogen was localized in the nucleus, chloroplasts and osmiophilic inclusions of the carpospore. Trace amounts of nitrogen were also found in cell walls, starch grains and in the embedding material.

The use …

Ultrastructural Variation In Enamel Of Australian Marsupials, C. F. Gilkeson, K. S. Lester

Scanning Microscopy

This paper initiates a survey of the enamel of fossil and extant Australian marsupials by scanning electron microscopy. Enamel was examined from 17 extant and 11 extinct marsupials. Assessment was made of prism packing pattern, prism course, tubule presence, tubule size and distribution. Values calculated were: prism diameter; prism axis ratio; cross-sectional prism area; cross-sectional ameloblast area; and numerical prism density.

Three different prism packing arrangements were found for extant and fossil marsupials within the classical Pattern 2. The Pattern 1 arrangement found in three extant species was relatively unexpected given the general acceptance of Marsupialia as having Pattern 2 …

Surface Studies Of Calcium Oxalate Dihydrate Single Crystals During Dissolution In The Presence Of Stone-Formers' Urine, M. Akbarieh, R. Tawashi

Scanning Microscopy

Dissolution of calcium oxalate dihydrate (COD) single crystals was studied at different pH levels and in different dilutions of stone formers' (SF) urine. The Fourier descriptors of the contour were determined during dissolution of COD using a quantitative morphological technique. The surface ruggedness of COD single crystals was determined from fractal analysis. The results obtained were compared with COD single crystals behavior in different dilutions of normal urine previously reported. The shape parameters and surface geometry of the dissolving COD crystals were significantly different in normal and SF urine. The data suggest that the shape descriptors and fractal geometry is …

Dentin: A Dynamic Substrate - A Review, David H. Pashley

Scanning Microscopy

The structure of dentin is unusual in that the number and size of its tubules changes as one moves from the periphery toward the pulp chamber. Near the pulp, the tubules are very close together and the water con tent of this deep dentin is high. Near the enamel, the tubules are far apart, occupying less than 1% of the surface area. When enamel or dentin is cut, the surface becomes covered by an adherent layer of cutting debris called the smear layer. Its composition presumably reflects the composition of the underlying dentin. It is only about 1 μm thick …

Scanning Optical Microscopy Of Semiconductor Materials And Devices, C. J. R. Sheppard

Scanning Microscopy

In the scanning optical microscope a focused light spot is used to illuminate the object and some property monitored as the spot is scanned relative to the object to build up an image. By monitoring different properties it is thus possible to use the scanning optical microscope in a wide range of imaging modes, which can be used to give much information concerning the structure and properties of semiconductor materials and devices. In the optical-beam induced current method the focused light spot generates electronic carriers in a semiconductor specimen, and the resultant current monitored. The technique can be used to …

Vascular "Sphincter" And Microangioarchitecture In The Central Nervous System: Constriction Of Intraparenchymal Blood Vessels Following A Treatment Of Vasoconstrictive Neurotransmitter, K. Nakai, Y. Naka, H. Yokote, T. Ikatura, H. Imai, N. Komai, T. Maeda

Scanning Microscopy

The site of action of neuropeptide Y (NPY), a potent vasoconstrictive neurotransmitter, on the intraparenchymal blood vessels in the rat parietal cortex was demonstrated using a corrosion cast technique with scanning electron microscopy. Our observations were confined to the cortical area where the regional cerebral blood flow (rCBF) had been reduced significantly by in situ application of NPY. A striking finding in that area was the diffuse narrowing of the perforating arteries in the upper cortical layers. Ring-like compressions on the corrosion casts, presumably formed by active vascular sphincters along the arteries, capillaries and venules within the brain parenchyma, seemed …

Measurement Of Fungicide Smoke Application By Electron Beam Analysis, C. R. Krause, C. C. Powell

Scanning Microscopy

Low volume fungicide smoke particle deposits were studied with scanning electron microscopy and energy dispersive X-ray analysis. Under greenhouse conditions, particles deposited on Rhododendron leaf surfaces and onto inert, carbon planchets adjacent to Rhododendron leaves were characterized by electron beam analysis. Angular particles containing chlorine, identified as vinclozolin deposition, were quantified on a per unit area basis. Leaf samples collected from plants immediately adjacent to the smoke applicator had more particles than leaf samples collected elsewhere. More deposition was measured on leaf surfaces than on inert planchet surfaces. This study increased our knowledge about the effectiveness of using less fungicide …

The Use Of Scanning Electron Microscopy For Investigations Into The Three Dimensional Organisation Of The Interphase Nucleus, T. D. Allen, P. M. O'Connor

Scanning Microscopy

In an attempt to elucidate three dimensional information on the organisation of the nucleus, nuclei have been extracted from ascites tumour cells or tissue culture cells by a variety of biochemical techniques, and prepared for high resolution scanning electron microscopy using an osmium-thiocarbo-hydrazide infiltration procedure which has previously proved successful for analysis of chromosome structure. Nuclei were prefixed with either Methanol-Acetic acid, glutaraldehyde or formaldehyde and then extracted by a variety of detergents with the aim of a 'biochemical dissection' of their outer elements to allow surface visualisation of the nuclear lamina. Continued extraction removed all aspects of the nuclear …

Fine Structure And Organ Culture Of Chick Embryo Dorsal Aorta, C. Ward Kischer, Michael Jaqua

Scanning Microscopy

Embryonic blood vessels have not been grown in organ culture, in a way which might easily submit them to studies of vascular organogenesis. The chick embryo dorsal aorta is easily accessible and relatively simple to explant to culture. Its organ culture may provide a model for wounding and repair of the intima and/or media and provide a model for studies of growth (or maintenance) and differentiation. Fresh dorsal aorta and its organ culture from the chick embryo was characterized morphologically by light microscopy scanning (SEM) and transmission electron microscopy (TEM) from days 4 to 18. Explants were incubated up to …