Biology Commons^™

Urinary Calculi: Review Of Classification Methods And Correlations With Etiology, M. Daudon, C. A. Bader, P. Jungers, O. Beaugendre, M. P. Hoarau

Scanning Microscopy

Current physical and chemical methods available for urinary stones analysis are critically reviewed. No one method is sufficient to provide all the clinically useful information on the structure and composition of the stones. We show that a combination of refined morphological and structural examination of stone with optical microscopy, complemented by compositional analysis using infrared spectroscopy of the core, cross-section and surface of calculi, provides a precise and reliable method for identifying the structure and crystalline composition, and permits quantification of stone components while being highly cost effective. Using such morphoconstitutional studies leads to a classification of urinary stones in …

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.

Surface Morphology And Strain Relief In Surfactant Mediated Growth Of Germanium On Silicon (111), M. Horn-Von Hoegen, M. Pook, A. Al Falou, B. H. Müller, M. Henzler

Scanning Microscopy

The growth of Ge on Si is strongly modified by adsorbates called surfactants. The relevance of the stress on surface morphology and the growth mode of Ge on Si(111) is presented in a detailed in situ study by high resolution low energy electron diffraction (LEED) during the deposition. The change from islanding to layer-by-layer growth mode is seen in the oscillatory intensity behaviour of the 00-spot. As a strain relief mechanism, the Ge-film forms a microscopic rough surface of small triangular and defect-free pyramids in the pseudomorphic growth regime up to 8 monolayers. As soon as the pyramids are …

Human Chromosomes: Evaluation Of Processing Techniques For Scanning Electron Microscopy, O. H. Sanchez-Sweatman, E. P. De Harven, I. D. Dubé

Scanning Microscopy

Methods for scanning electron microscopy (SEM) of chromosomes have been developed in the last two decades. Technical limitations in the study of human chromosomes, however, have hindered the routine use of SEM in clinical and experimental human cytogenetics. We compared different methodologies, including metal impregnation, air drying and specimen coating. SEM preparation of human chromosomes in which osmium impregnation is mediated by tannic acid, yielded more reproducible results when compared with osmium impregnation protocols previously described. The level of osmium impregnation was systematically evaluated by imaging chromosomes in the backscattering mode. Critical point drying and a light gold-palladium coating were …

Keynote Paper: The Scanning Electron Microscope (Sem) Supplemented By The Polarized Light Microscope (Plm), And Vice Versa, Walter C. Mccrone

Scanning Microscopy

The scanning electron microscope (SEM) yields excellent topographic and other shape information and, when fitted with an energy dispersive system (EDS), elemental composition. The polarized light microscope (PLM) on the other hand, delivers information on the internal properties of small particles, fibers, and films. By determining optical properties as well as shape, PLM determines molecular, rather than elemental, composition. Both SEM and PLM have impressive records for problem solving in the research and development world and each is usually applied without aid from the other. Examples are given of important problems that have been solved by supplementary PLM with SEM …

The Vascularization Of The Kidney Of The Eel (Anguilla Anguilla - Osteichthyes) In The Freshwater Habitat, Hans Ditrich, Heinz Splechtna

Scanning Microscopy

The renal vascular system of eels (Anguilla anguilla L.) in freshwater has been investigated using light-, transmission electron-, and scanning electron microscopy of vascular corrosion casts and critical-point dried specimens. The morphology of the kidney exhibits a highly evolved, unpaired, spindle-shaped form. The renal tissue extends partially into a recessus dorso-caudal to the anus. Renal glomeruli are comparatively large (100.8 μm +/-17 standard deviation) and well vascularized. They are arranged in grape-like clusters around the intrarenal arteries. Closely neighbouring glomeruli can be surrounded by incompletely separated Bowman's capsules sharing the same renal tubule. The peritubular capillary plexus is …

Identification Of Ion Transport Compartments In Turtle Urinary Bladder, P. Fraunberger, A. Dörge, P. Buchinger, F. X. Beck, K. Thurau

Scanning Microscopy

To identify the turtle urinary bladder cells involved in Na and Cl absorption and Hand HCO₃ secretion cellular electrolyte concentrations and uptake of Br and Solutrast were determined using electron microprobe analysis. Whereas inhibition of transepithelial Na transport by ouabain (reversion of short circuit current) led to a pronounced K-Na exchange in granular, and most of the basal cells, surface CA-cells and some basal cells were ouabain insensitive. Surface CA-cells could be divided into a large Cl-rich and a small Cl-poor population. Since the ouabain-induced K-Na exchange could be completely prevented by blocking passive luminal Na entry by amiloride, …

Preparation Of Dinosaur Fossils For Scanning Electron Microscopic Evaluation Of Bone Histology, C. Barreto, R. M. Albrecht

Scanning Microscopy

The quality of preservation is a major determinant of the amount and kind of information to be derived from a paleontological specimen. Various fossilization regimes may produce specimens that contain biological information on a microscopic level. Light microscopic inspection of adolescent fossil dinosaur bones from the Two Medicine Formation (northwestern Montana) revealed that precise preservation of tissue may occur at a cellular level. In the following report, we test and compare techniques of specimen preparation for examination by scanning electron microscopy and illustrate an example of faithful preservation of dinosaur bone histology.

Evaluation Of The Surface Roughness Of Cystine Stones Using A Visible Laser Diode Scattering Approach, R. Thibert, B. Dubuc, M. Dofour, R. Tawashi

Scanning Microscopy

To understand the processes of fragmentation and the chemical reactivity of solids, proper characterization of surface topography is crucial. This paper describes a non-destructive technique of quantifying the surface roughness of cystine renal stones, using visible laser diode scattering and fractal geometry. Fragments of cystine stones were mounted on microscope slides and coated by a carbon-sputtering apparatus. The slides were placed under a dynamic active-vision system, using a visible laser diode to measure three-dimensional surface coordinates. The data obtained were analyzed by fractal geometry. Surface fractal dimensions were determined by the variation method. The results showed that the surface of …

Scanning Electron Microscopy Of Vascular Smooth Muscle Cells From Spontaneously Hypertensive Rats, William J. Krizmanich, Robert M. K. W. Lee

Scanning Microscopy

The fine structure of vascular smooth muscle cells from large mesenteric arteries of adult (28 weeks) spontaneously hypertensive rats and Wistar-Kyoto rats was studied using scanning electron microscopy (SEM). The effect of the digestion method for SEM on tissue size and smooth muscle cell size was also studied using morphometric analysis. A significant reduction in cell size (42-43%) was present after critical point drying, based on the reduction in volume to surface ratio of smooth muscle cells. However, percent change of volume density and volume to surface ratio of smooth muscle cells after digestion and after critical point drying, was …

Reversible And Irreversible Effects Of Temperature On Amelogenesis Of Hamster Tooth Germs In Vitro, J. H. M. Wöltgens, D. M. Lyaruu, Th. J. M. Bervoets, A. L. J. J. Bronckers

Scanning Microscopy

Hamster first hamster molar tooth germs in early secretory stage of amelogenesis were cultured for one day in vitro at 6°C, 22°C, 37°C or 45°C in the presence of ³H-proline, ⁴⁵Ca and ³²P-orthophosphate. Other explants were cultured without these labels and after culture examined by histology. The highest temperature tested was lethal to the explants, decreased total dry weight and rapidly increased total uptake of the radio-labelled mineral ions, probably merely due to physicochemical modification of the existing preculture minerals. Optimal synthesis and secretion of amelogenins were measured at physiological temperature (37°C). Effects of exposure to both …

Electron Acoustic Signal Of Metallic Layers Over A Semiconductor Substrate, J. F. Bresse

Scanning Microscopy

Calculations have been made for the electron acoustic signal in the case of one and two metallic layers deposited over a semiconductor substrate. The temperature distribution as function of the depth has been determined by taking into account the power absorbed in the metallic layers and the substrate. We have considered strain-free and constrained layers. Experimental results have been obtained for a single metallic layer (Au, W, Pd, Mo, Mn, Ti) deposited over GaAs and for Au-Ti contacts. Comparison between experiments and calculations allows us to determine whether the layers are constrained or not.

A Scanning Tunneling Microscopy Study Of Vanadium Oxide, Takanori Oshio, Yoshiyuki Sakai, Tohru Moriya, Shaw Ehara

Scanning Microscopy

Atomic resolution images of the (010) surface of a divanadiun pentoxide (V₂O₅) single crystal were successfully obtained by the use of a scanning tunneling microscope (STM).

The images of the filled states at sample bias voltage, Vs = -2 V and the empty states at Vs = +2 V correspond to oxygen and vanadium ions, respectively.

As for the vanadium ion sites, an additional peak of the electronic states at the conduction band edge due to the defects of vanadyl oxygen ions was found in the normalized conductance spectrum through the tunneling spectroscopy (TS) measurement.

Fungiform Papillae Of The Pig And The Wild Boar Analyzed By Scanning Electron Microscopy, C. A. Chamorro, P. De Paz, J. G. Fernández, L. Anel

Scanning Microscopy

Fungiform papillae of wild boar and pig were studied by scanning electron microscopy (SEM). Four regions were defined on the tongue: rostral, medial and caudal thirds and lateral sides. Morphologically the fungiform papillae correspond with their denomination. Rostral and lateral tongue regions presented the largest average number of fungiform papillae. Taste pores opened onto the upper surface of the papillae and were easily identifiable by SEM. The total number of fungiform taste pores from both animals was the highest reported in the literature. The lateral papillae of wild boar and pig contained the largest average number of pores per papilla. …

Morphology Studies Of Iron-Manganese Thin Films, G. Mathew, K. -W. Ng, A. R. Sethuraman, J. M. Stencel

Scanning Microscopy

Fe-based catalysts are known to be effective for Fischer-Tropsch synthesis from coal but are sensitive to sulfur poisoning. Addition of manganese to these catalysts has been proposed in an effort to combat this catalyst deactivation. To investigate the fundamental physical aspects of Mn incorporation into Fe, different compositions of model thin films of Fe-Mn, ranging from 100% Fe to 100% Mn were studied for the very first time, using scanning tunneling microscopy (STM), atomic force microscopy (AFM) and scanning electron microscopy. Our preliminary results indicate that the grain size of iron varied from 50 nm to 150 nm using the …

Scanning Electron Microscopy Of Muscle Myofibrils After High Pressure Freezing And Freeze-Substitution-Staining, M. Malecki, M. L. Greaser

Scanning Microscopy

A novel approach to study the three dimensional ultrastructure of organelles and cells by means of scanning electron microscopy is described. Muscle myofibrils have been used in the development of the techniques since their structure is well characterized using conventional electron microscopic methods. Myofibrils in rigor buffer (with no cryo-protectants or pressure sealants) were frozen at high pressure (2300 bar) within specially designed chambers. The frozen specimens were then freeze-substituted-stained with methanol containing tungsten and iron salts and finally critical point dried. These methods allowed scanning electron microscopic observations of the organization of individual filaments within whole myofibrils over several …

Application Of Scanning Electron Microscopy And X-Ray Analysis To Urinary Tract Cancer In Animals And Humans, Martin Cano, Toru Suzuki, Samuel M. Cohen

Scanning Microscopy

Scanning electron microscopy (SEM) has proven useful in various aspects of urinary bladder carcinogenesis research and these are reviewed as they pertain to our research involving sodium saccharin in the rat. Sodium saccharin-carcinogenesis in rats requires administration at high doses beginning at birth or earlier. Administration beginning at ages of 5 weeks or later results in much lower incidences of bladder tumors. Methods were developed for examining the rat fetal and neonatal bladder to further evaluate effects at these critical ages. Several significant differences were found by SEM between the fetal bladder compared to the-adult. The typical polygonal superficial cells …

Quantitative Scanning Electron Acoustic Microscopy Of Silicon, M. Domnik, L. J. Balk

Scanning Microscopy

So far results of scanning electron acoustic microscopy (SEAM) have retained a widely qualitative meaning only due to the enormous uncertainty in understanding sound generation and contrast mechanisms in SEAM micrographs. In this work, a detailed treatment of these mechanisms has been undertaken for silicon resulting in precise knowledge of the signal generation processes and a well understood interpretation of the contrast mechanisms involved in imaging thermo-mechanical and electronic features.

Scanning Electron Microscopy Of Styrene-Methylethylketone Casts Of The Airway And The Arterial System Of The Lung, Teruyuki Hojo

Scanning Microscopy

The method of making casts of airways and the pulmonary arterial system using a styrene polymer resin is described. A human and a dog were used as models. The viscosity of this resin ranges between 40 and 60 dPa/s at 24°C. The elastic rubber tube used for resin injection allows a constant perfusion pressure, i.e., 44 mm Hg and 110 mm Hg for airway and vascular filling, respectively. The casts obtained using this method are suitable both for macro- and microscopic analysis. Shrinkage during polymerization is minimal. Moreover, a preceding lavage is not necessary. Scanning electron microscopy (SEM) of cast …

Electron Probe Micro-Analysis Of Human Dental Pulp Stones, O. Le May, J. C. Kaqueler

Scanning Microscopy

The mineral composition of ten human dental pulp stones presenting various morphological aspects has been studied by electron probe micro-analysis. The denticles were composed of two major chemical elements Ca and P with mean concentrations 32.12% and 14.69% respectively giving a Ca/P weight ratio of 2.19 which is very close to the weight ratio of pure stoichiometric hydroxyapatite (2.15). The concentration of some other elements was much lower (0.88% for F ; 0.75% for Na ; 0.51% for Mg). The other analysed constituents (K, Cl, Mn, Zn, Fe) were present at trace concentrations. The mineral composition of sound human dentine …

Letter To The Editor By M.B. Engel And H.R. Catchpole Relating To: "Can We See Living Structures In The Cell" [By G.N. Ling, Scanning Microscopy Vol. 6, P. 405-450 (1992)] And Reply By G.N. Ling, M. B. Engel, H. R. Catchpole

Scanning Microscopy

Dear Editor,

As workers in the field of ionic equilibrium in extracellular matrices and cells, and as contributors to this Journal of papers supporting an alternative explanation to that represented by the dominant schools of active transport (ionic pumps), we are surprised by the statement of Ling (1992, p. 449) which appears to limit published criticism of those schools to himself and A.S. Troshin. By an odd coincidence, our abstract (Catchpole et al., 1951) on the distribution of potassium and sodium through selective action of the cations with ground substance and water appeared simultaneously with that of Ling (1951): "Tentative …

Role Of Adhesion Molecules In The Mechanism Of Non-Mhc (Major Histocompatibility Complex) Restricted Cell-Mediated Cytotoxicity, Walter Malorni, Francesca Iosi, Daniela Zarcone, Carlo Enrico Grossi, Giuseppe Arancia

Scanning Microscopy

Adhesion molecules involved in the interaction between immune system effector cells and tumor targets are surface molecules which contribute to the formation of cell-to-cell contacts and belong to the integrin family. In this paper, the role played by the adhesion molecules in the process of cell-mediated cytotoxicity is reviewed. Furthermore, the contact area between effector and target cells has been analyzed by scanning electron microscopy. This region, termed "closed chamber", seems to contribute to killing efficiency by creating an intimate contact region in which cytotoxic factors can easily induce lethal hit in target cell. Thus, the extension of the closed …

Radiation-Induced Neoplastic Transformation Of Human Cells, J. S. Rhim, P. Thraves, A. Dritschilo, M. R. Kuettel, M. -S. Lee

Scanning Microscopy

Ionizing radiation can induce cancers in humans and animals and can cause in vitro neoplastic transformation of various rodent cell systems. However, numerous attempts to achieve neoplastic transformation of human cells by radiation have generally proven unsuccessful. Neoplastic transformation of immortalized human epidermal keratinocytes by X-ray irradiation has recently been reported. The carcinogenic effect of radiation on cultured human cells will be briefly reviewed. The current state-of-the-art in radiation-induced transformation of human cells in culture is presented. This will provide insight into the molecular and cellular mechanisms in the conversion of normal cells to a neoplastic state of growth.

Identification Of The Physical Modification Threshold Of Dentin Induced By Neodymium And Holmium Yag Lasers Using Scanning Electron Microscopy, J. M. White, H. E. Goodis, G. W. Marshall Jr., S. J. Marshall

Scanning Microscopy

Laser application to dentin has been advocated to modify the dentin substrate for restorative procedures. We examined the minimum energy density required to physically modify the dentin surface using 1.06 μm and 1.32 μm Neodymium:Yttrium-Aluminum-Garnet (Nd: YAG) and 2.10 μm Holmium-YAG (Ho: YAG) lasers. Three millimeter thick dentin sections from the middle occlusal third of crowns of third molars were used. To determine the effect of surface preparation, the sections were ground to 240, 320, 400, 600 grit or polished to 0.5 μm. Smear layer was removed using 0.5 M EDTA for 2 minutes. Five single pulse repetitions at each …

Vascular Remodeling In Hypertension, Gary L. Baumbach, Shams Ghoneim

Scanning Microscopy

Cerebral arterioles in stroke-prone spontaneously hypertensive rats (SHRSP) paradoxically become more distensible, despite hypertrophy of the vessel wall. Cerebral arterioles in SHRSP also undergo remodeling with a reduction in external diameter. Based on these findings, we have proposed the concept that remodeling of cerebral arterioles may be an important mechanism, in addition to hypertrophy, for encroachment on the vascular lumen in SHRSP. The purpose of this review is threefold. First, consequences of vascular hypertrophy that have been proposed previously are reviewed with an emphasis on the hypothesis that encroachment on the vascular lumen by hypertrophy is an important mechanism …

Surface Chemical Reactions At The Atomic Scale: Gas Reactions With Semiconductors Studied With Scanning Tunneling Microscopy, R. S. Becker, Y. J. Chabal, G. S. Higashi, A. J. Becker

Scanning Microscopy

The vacuum tunneling microscope has been extensively utilized in the study of the surface atomic configuration of conducting materials. Analysis of features in both the tunneling images and in the tunnel junction I-V characteristic yields insight into a wide variety of processes occurring at surfaces. In the last few years, elementary chemical reactions occurring at surfaces have been examined in this manner, principally adsorption of simple gas species such as H₂, O₂, and NH₃ on semiconductors and metals. Adsorption sites have been deduced from changes brought about in surface configuration subsequent to gas exposure. The …

Recent Developments In Multichannel Raman Microprobing, J. Barbillat, M. Delhaye, E. Da Silva

Scanning Microscopy

This paper reviews the capabilities of multichannel Raman microprobing instruments with emphasis on some major innovative progress recently proposed which looks promising for the development of new fields of application. This new progress includes: confocal Raman microanalysis that provides better spatial resolution and background rejection, confocal Raman mapping that revitalizes the field of Raman imaging pioneered by us 20 years ago, the coupling of molecular Raman microanalysis to elemental electron microprobe, and finally, Raman spectroscopy with near-infrared excitation which permits avoiding the fluorescence limitation of visible Raman spectroscopy.

Anisotropic Secondary Electron Emission From Si(100) Surface Observed By Ultrahigh Vacuum Scanning Electron Microscopy, Yoshikazu Homma

Scanning Microscopy

The effect of surface atomic structure on secondary electron (SE) emission from a Si(100)2 X 1 surface is studied using an ultrahigh vacuum scanning electron microscope with an SE detector having angular resolvability. The double domain structure, alternate 2 X 1 and 1 X 2 domains, can be clearly imaged by SEs, indicating that the SE emission varies with the orientation of dimer rows on Si(100) surface: higher intensity in the direction parallel to the dimer rows and lower intensity in the perpendicular direction. The present results demonstrate that the SE emission is greatly influenced by the atomic configuration in …

Transmission Electron Microscopy And Nanoprobe Analysis Of Ferroelectric Thin Films, Maria Huffman, Mowafak M. Al-Jassim, Chuck Echer

Scanning Microscopy

Thin-film ceramic materials have a variety of electronic applications. Several deposition techniques are currently being used to produce such films with specific properties. For example, rf-sputtered ferroelectric perovskite films, with total thicknesses less than 0.5 μ.m, are being integrated with semiconductor devices as elements for non-volatile memories. Since there is a definite need to characterize these thin films after deposition, electron microscopy has been utilized as one of the most powerful techniques available for examining their morphology and microstructure. Transmission electron microscopy (TEM) examination of these oxides proved difficult. New TEM sample preparation techniques had to be developed in order …

X-Ray Topography, A. Zarka

Scanning Microscopy

The purpose of this paper is to discuss some elements of dynamical theory and to introduce some basic ideas on defect image formation in X-ray topographs. After some explanations of the basic principles of dynamical theory of X-rays, examples of defect contrast are given. Two examples of studies of quartz single crystals by X-ray topography are developed. First, the analysis of the X-ray spherical wave topographs of various Y-cut plates of synthetic quartz crystals show that the coherence of the lattice between the seed and the grown crystal is directly related to the density of the dislocations present in the …