Life Sciences Commons^™

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 …

Observations Of Colloidal Gold Labelled Platelet Microtubules: High Voltage Electron Microscopy And Low Voltage-High Resolution Scanning Electron Microscopy, R. M. Albrecht, J. Prudent, S. R. Simmons, J. Pawley, J. J. Choate

Scanning Microscopy

18 nm colloidal gold-antitubulin and 4 nm colloidal gold-antitubulin were used to label microtubules in adherent, fully spread platelets. Both sizes of marker effectively labelled microtubules in the partially extracted platelets. However only the 4 nm gold penetrated the dense microfilament matrix of the inner filamentous zone so that portions of microtubules within this cytoskeletal zone could be tracked. The gold marker could be visualized well with 1 MeV high voltage transmission EM and with 5 kV or greater secondary imaging or 20 kV backscattered imaging of carbon only coated samples. 1 kV secondary imaging permitted high resolution imaging of …

The Radiomycetaceae (Mucorales; Zygomycetes). Calcium Oxalate Crystals On The Sporangiolar Wall And Aerial Hyphae, G. L. Benny, S. R. Khan

Scanning Microscopy

Calcium oxalate crystals occur on the sporangiolar appendages and aerial hyphae of the two known genera (Hesseltinella, Radiomyces) of the mucoralean family Radiomycetaceae. In Hesseltinella the sporangiolar appendages are acicular with a polygonal, square, or hexagonal, discoid base. The appendage core consists of calcium oxalate and is composed of two portions: (1) a round, acicular spine with a more or less hexagonal base, and (2) a square, polygonal, or hexagonal, discoid base with a central perforation that generally contains the spine base. Both portions of the spine core appear to be readily separable. In species of Radiomyces the …

Quantitative Margin Analysis In The Scanning Electron Microscope., J. F. Roulet, T. Reich, U. Blunck, M. Noack

Scanning Microscopy

Interface between restorative materials and tooth hard substances must be morphologically as perfect as possible to avoid plaque accumulation and subsequent secondary caries or pulpal diseases. Therefore the marginal behavior of restorations is an important parameter to predict their longevity.

Morphologically, the quality of margins is characterized by different well defined criteria. Using a replica technique it is possible to assess the complete marginal circumference of restorations in the SEM. Margins of restorations show a large variety of their morphology. This publication describes a method to quantify the quality of dental restorations.

The restoration margins are traced on the SEM …

Optical Design Considerations In Confocal Scanning Microscopy, T. Wilson

Scanning Microscopy

We review the properties and applications of confocal optical systems. We concentrate on non-fluorescent reflection systems and on applications which make use of the unique optical sectioning property of these instruments to provide three-dimensional images. A crucial design choice concerns the form and size of the detector. We therefore concentrate on the role of the detector size on the strength of the optical sectioning. We find that although the sectioning becomes weaker as the detector sizes where the sectioning remains essentially constant. We also consider the role of lens aberrations which are inevitably present and find, inter alia, that these …

Stimulation Of Collagen Formation In The Intestinal Anastomosis By Low Dose He-Ne Laser, David T. Yew, Winnie W. Y. Li, K. M. Pang, Y. C. Mok, C. Au

Scanning Microscopy

The effect of low dose He-Ne laser on the healing of intestinal anastomosis was studied in the albino rat. A small piece of jejunum was removed from each rat and the ends sutured back with a simple interrupted pattern. In the experimental animal, the anastomosis was Irradiated through an optic fiber with a He-Ne laser (1 mW) for 15 minutes whereas in the control animal, the anastomosis was not irradiated. The differences between the two groups were compared by histology, transmission electron microscopy, scanning electron microscopy and autoradiography 3 and 7 days after operation. The laser treated experimental animals demonstrated …

Complementary Surface Characterization Of Chalcopyrite By Electron Microscopy, Electron Spectroscopy, And Optical Reflectance, P. H. Ruzakowski, P. H. Holloway, G. Remond

Scanning Microscopy

Surface oxidation of polished natural specimens of chalcopyrite (CuFeS₂) at temperature between 23°C and 300°C in air has been characterized by Auger electron and X-ray photoelectron spectroscopies. The reaction products consisted of an outer iron oxide layer and an intermediate copper rich sulfide layer. Several different oxides and sulfides were consistent with the electron spectroscopy data, so specimens were analyzed as a function of time and temperature at selected 20 μm diameter areas with an optical microreflectometer (OMR). Since the optical properties of a compound are unique, a reflectance model with three homogeneous layers was used to calculate …

Visualization And Analysis Techniques For Three Dimensional Information Acquired By Confocal Microscopy, G. J. Brakenhoff, H. T. M. Van Der Voort, M. W. Baarslag, B. Mans, J. L. Oud, R. Zwart, R. Van Driel

Scanning Microscopy

Confocal Scanning Laser Microscopy (CSLM) is particularly well suited for the acquisition of 3-dimensional data of microscopic objects. In the CSLM a specific volume in the object is sampled during the imaging process and the result is stored in a digital computer as a three-dimensional memory array. Optimal use of these data requires both the development of effective visual representations as well as analysis methods. In addition to the well known stereoscopic representation method a number of alternatives for various purposes are presented. When rendering in terms of solid-looking or semitransparent objects is required, an algorithm based on a simulated …

Quantitative Electron Microprobe Analysis Of Cryosections, Albert J. Saubermann

Scanning Microscopy

There are numerous approaches to preparation and analysis of biological specimens which have been developed in many laboratories involving the use of cryosections. Because there is no clear consensus on how such samples should be produce or analyzed, it can be a formidable problem to choose or even review possible options. Therefore, it is the purpose of this tutorial to consider, in an instructional manner the problems of specimen preparation and analysis in terms of the solutions and procedures used by the author. The discussion, consequently. focuses on the problems of specimen preparation and analysis as seen by the author. …

Monte Carlo Calculations Of Secondary Electron Emission, Suichu Luo, David C. Joy

Scanning Microscopy

Monte Carlo calculations of slow secondary electron (SE) generation have been performed. Construction of a model for SE production involves three distinct steps, determining the trajectory of the incident electron, computing the rate of secondary electron generation along the trajectory of both primary and backscattered electrons, and finally calculating the secondary electron emission by using a hybrid model of the exponential decay law and cascade process. The incident electron trajectory is computed using a plural scattering Monte Carlo model. For secondary electron generation our models take into account all possible creation processes of SE resulting from the interaction of primary …

Ion Microscopy: A New Approach For Subcellular Localization Of Labelled Molecules, E. Hindie, P. Hallégot, J. M. Chabala, N. A. Thorne, B. Coulomb, R. Levi-Setti, P. Galle

Scanning Microscopy

Secondary ion mass spectroscopy (SIMS) was used to obtain images representing the intracellular distribution of molecules labelled with carbon 14.

Deoxyadenosine labelled with carbon 14 was added to a cultured human fibroblast cell medium, and the intracellular distribution of this molecule was studied using three different SIMS instruments: the CAMECA IMS 3F and SMI 300 ion microscopes and the UC-HRL scanning ion microprobe.

Carbon 14 distribution images obtained by this method show that deoxyadenosine U-C14 is present in the cytoplasm as well as the nucleus, with a higher concentration in' the nucleoli. Our study clearly demonstrates that ion microscopy is …

Tubuloreticular Reorganization Of Cytomembranes In Cells Treated With With Human Alpha Interferons - A Review, P. M. Grimley, S. Ray, M. Kostianovsky, B. Rupp, Y. -H. Kang, D. Feldman

Scanning Microscopy

Human alpha interferons (IFN-a) cause a reorganization of internal cell membranes into tubuloreticular inclusions (TRI). Morphogenesis and cytochemistry indicate a pre-Golgi intracisternal origin from the endoplasmic reticulum. Clinically, TRI formation in human blood mononuclear cells correlates with systemic IFN-a treatment or with endogenous overproduction of IFN-a in viral or autoimmune diseases (e.g., rubella syndrome, AIDS, systemic lupus erythematosus). In vitro, TRI formation can be produced by treatment of Daudi lymphoblasts or vascular endothelial cells with IFN-a, and is blocked by actinomycin-D. In Daudi lymphoblasts or vascular endothelial cell cultures, TRI formation parallels induction of 2'-5' A synthetase, inhibition of …

Restorative Dental Materials: Scanning Electron Microscopy And X-Ray Microanalysis, Grayson W. Marshall Jr., Sally J. Marshall, Stephen C. Bayne

Scanning Microscopy

Restorative dental materials include the materials used to repair damaged teeth and/or replace missing teeth. The definition could be extended to include a much broader group of dental materials, but this paper concentrates only on those materials used to restore the crown portion of damaged teeth. Auxiliary materials, materials for removable denture prostheses, and root canal materials are excluded. Progress and recent research utilizing SEM (Scanning Electron Microscopy), EDS (Energy Dispersive Spectroscopy), and some related methods are presented for the following dental materials: dental amalgam, enamel and dentin bonding agents, dental composites, dental cements, casting alloys for crowns and bridges, …

Attachment Of Plasma Membranes Of Cultured Cells To Silicon Chips For High Magnification Imaging In Scanning Electron Microscopy, Klaus-Ruediger Peters, William W. Carley

Scanning Microscopy

In the membrane preparation method described in this paper, a polylysine-coated silicon chip is adsorbed to the exposed apical surface of a cell monolayer. Upon removal, the adsorbed chip separates the plasmalemma from the residual bodies of the cultured cells. This sandwich-membrane separation approach simplifies access to the cytoplasmic aspects of both the apical and the basal plasmalemma which remains on the culture substrate and is covered to a varied extent by cytoplasmic infrastructures. To stabilize the attached membranes, small crosslinking agents are used in a controlled osmium impregnation. Large crosslinkers are avoided since they induce thickening of fine structures. …

A Rapid Method For Observing The Internal Morphology Of Amphibian Embryos, S. C. Smith, J. B. Armstrong, D. C. Hoppe

Scanning Microscopy

A simple, rapid method for visualizing the internal morphology of amphibian embryos is described. Fixed embryos of Ambystoma mexicanum are surrounded with commercial embedding material and are frozen. Internal structure is revealed by cutting the embryos with a cooled scalpel or razor blade, removing the frozen embedment with an aqueous buffer, and processing the halved embryos for scanning electron microscopy (SEM). This technique allows the internal anatomy of the embryo to be viewed but is much simpler and more rapid than previously described techniques. It should therefore prove useful for understanding and teaching the three-dimensional relationship between tissues in developing …

A New Versatile Holder For The Calibrating Standard Used For Quantitative Analysis In Jeol 840 Sem, Michael Dvorachek

Scanning Microscopy

An improved holder has been designed for a cobalt calibrating standard used in an EDS Link 10,000 system attached to a JEOL 840 SEM. This holder allows the calibration of the EDS software for a wide range of samples differing in size, surface and height. These differences usually cause difficulties during quantitative analyses. The new holder allows the position of the cobalt to be adjusted according to the size and height of the sample.

Coherence In Energy Loss Spectra Of Plasmons, P. Schattschneider, P. Pongratz

Scanning Microscopy

Theoretical approaches to coherent excitation of two plasmons in a metal do not well agree with one another and with experimental results from electron energy loss spectrometry (EELS). We measured EELS spectra of polycrystalline aluminum films for various specimen thickness. By means of a new deconvolution method for multiple scattering, we obtained values between 0.6% and 3.3% for the probability F₂ of the coherent double plasmon event, relative to the single plamon event.

A review of earlier experimental as well as theoretical investigations is given. Our results together with a discussion of possible sources of error confirm our earlier …

Field Ion Microscopy And Atom-Probe Mass Spectroscopy: Techniques And Selected Applications, G. L. Kellogg

Scanning Microscopy

The techniques of field ion microscopy and atom-probe mass spectroscopy are reviewed with emphasis on the general operational principles of the instruments and selected applications in the area of surface science. The single atom imaging capability of the field ion microscope is shown to make it uniquely suited to the study of detailed, atomic processes on clean metal surfaces. As examples, investigations of single-atom surface diffusion, cluster nucleation, and surface reconstructions are discussed. The ability of the atom-probe mass spectrometer to determine the chemical identity of selected atoms observed in the field ion microscope image is shown to be useful …

Dynamic Analyses Of Lymphoblast Membranes Exposed To Alpha Interferon Using Flow Cytometry And Fluorescence Recovery After Photobleaching, E. Balint, A. Aszalos, P. S. Pine, P. M. Grimley

Scanning Microscopy

Interferons represent a major group of the biologic response modifiers which exert multipotent effects upon cell growth, cytodifferentiation and immune functions. Previous experimental studies with alpha interferon (IFN-𝝰) have suggested that modulation of transmembrane signaling could be a critical determinant in the bioregulatory diversity. To determine whether any initial changes at the plasma membrane would directly correlate with one or more actions of IFN-𝝰, we investigated cultures of Daudi lymphoblasts which are uniquely susceptible to growth inhibition. Complementary biophysical techniques were applied. In one approach, changes in plasma membrane ion flux were measured by flow cytometry, using a fluorescent dye …

Vascularization Of Male Gonads In Blennius Pavo (Teleostei, Blenniidae) As Revealed By Scanning Electron Microscopy Of Vascular Corrosion Casts, F. Lahnsteiner, A. Lametschwandtner, R. A. Patzner, H. Adam

Scanning Microscopy

The vascular architecture of male gonads of Blennius pavo is studied by scanning electron microscopy of vascular corrosion casts. Arterial supply to the gonads is by a branch of the first ventral segmental artery of the tail. From the surface of the gonads, this vessel gives rise to branches which supply testes, spermatic ducts, testicular glands, blind pouches, urogenital sinus and urogenital papilla. The testis has a rope-ladder-like capillary network around the seminiferous tubules, while in the testicular gland the capillary network is irregular in form. The spermatic ducts are found to have an exterior capillary network located in the …

The Floating Gate Metal Oxide Semiconductor Transistor, A Device For Low Kv E-Beam Charging Evaluations, P. Girard

Scanning Microscopy

Today the scanning electron microscope has become the tool for investigations on integrated circuits. In e-beam testing ore-beam reconfiguration of VLSI, the effective charging conditions of top oxides are important. However due to the insulator nature of the zone impinged by the electrons, it is generally difficult to obtain quantitative information. Here we present and illustrate the use of floating gate MOS transistors for charging determination. The basic equations are derived from a physical model and a comparison is made with the evolution of the electrical characteristics of the devices under charge deposition. The effective charging yields are determined in …

Backscattered Electrons And Their Influence On Contrast In The Scanning Electron Microscope, F. Hasselbach, H. -R. Krauss

Scanning Microscopy

The backscattered electron (BSE) induced secondaries (SE2) emerge from an area that is usually many orders of magnitude larger than the area in which the impinging primary probe releases secondary electrons (SE1). These SE2 secondary electrons form a) an undesired background signal in high resolution scanning micrographs and b) are responsible for the well known proximity effect in electron beam lithography. In this paper we focus our attention on the first topic exclusively: we discuss the complex influence of the SE2 on contrast in SEM micrographs (neglecting the components SE3 and SE4). We do this on the basis of our …

Investigation Of Surfaces And Interfaces By Electron Optical Methods, H. Seiler

Scanning Microscopy

The combination of methods for surface analysis with electron microscopes (EM) gives the possibility for surface and interface microanalysis. The paper deals with different methods a) for imaging of surfaces with high lateral resolution: Emission EM (EEM), Scanning EM (SEM), Reflection EM (REM) Transmission EM (TEM) using special preparation methods as replica techniques or cross section specimens b) for crystal structure investigation: Low and High Energy Electron Diffraction and Electron Chanelling Patterns and c) for material analysis using electron spectroscopy either of the emitted or scattered electrons.

The combination of all analytical methods in one instrument for surface microanalysis (SMA) …

The Role Of Energy Deposition Processes In The Understanding Of Laser Microprobe Analysis Mechanisms, Akos Vertes, Peter Juhasz, Marc De Wolf, Renaat Gijbels

Scanning Microscopy

After emphasizing the role of local energy deposition as a common feature of many microanalytical techniques we focus our attention to laser ionization processes in mass spectrometry of solids. Enhancement of ionization in the case of high power density laser pulses can be rationalized in terms of hydrodynamic equations. The mechanism of shock wave generation and plasma ignition as well as excess energy absorption is demonstrated. Model calculations show that a one component - one dimensional (1C-1D) description can account for such important features of the laser ionization process as energy distribution of the produced ions. The role of classical …

A Comparison Of The Elemental Concentrations In Tissue Thymocytes From Diabetic And Non-Diabetic Rats, A. Warley

Scanning Microscopy

The elemental concentrations in thymocytes from control and diabetic rats were studied by use of the techniques of cryofixation and X-ray microanalysis to determine whether any changes occur in the diseased state. Decreases in the concentrations of the elements P and K were found in thymocytes from the subcapsular and cortical regions of the gland in thymus tissue taken 4 days after the onset of diabetes. A decrease in the concentration of Mg was also found in thymocytes from the subcapsular region of the gland. These changes suggest that the metabolism of thymocytes in vivo is altered in the diabetic …

Concentrations Of Elements In Dying Thymocytes From The Thymus Gland Of Diabetic Rats, Alice Warley, I. W. Morris

Scanning Microscopy

Atrophy of the thymus gland occurs in rats made diabetic by a single injection of the drug streptozotocin. Histological studies show the presence of thymocytes with pyknotic nuclei in thymus tissue taken from diabetic animals. Analysis of the elemental content of the pyknotic cells was carried out on freeze dried frozen sections of thymus tissue using the technique of X-ray microanalysis. There was no loss of elements from cells which had undergone the early morphological changes characteristic of pyknosis and which showed the condensed chromatin of pyknotic nuclei. However as the cells shrank and lost the clear distinction between nucleus …

A Study Of Low Energy Ar+ Ion Bombardment Induced Lattice Damage In (100) N-Gaas By Channeling, S. K. Jindal, S. S. Lin, L. D. Brown, H. L. Marcus, M. A. Schmerling

Scanning Microscopy

It has been found that sputter cleaning of GaAs single crystals results in damage or loss of crystallinity in the first few tens of nanometers of the crystal. The damage is a result of both - energetic Ar ions impinging on and being incorporated in the GaAs surface and the resultant preferential sputtering of As from the GaAs lattice. A study of this damage which was done at room temperature and at -110 °C was made by the use of Selected Area Electron Channeling Patterns. The relationship between the degree of surface disorder, as shown by the pattern degradation, and …

X-Ray Analysis Of Biological Fluids: An Update, G. A. Quamme

Scanning Microscopy

X-ray analysis has been used for some twenty years to quantify elements including Na, K, Cl, Ca, Mg and phosphorous in biological fluid samples. The method consists of accurate pipetting of 50-150 pl samples and appropriate drying to form crystalline deposits. Quantitation is obtained by comparison of x-ray intensities with comparable standard crystalline deposits. Electon microprobe analyses have contributed much to our understanding of renal transport function including physiological controls and pathological influences on the tubular handling of the major elements. New approaches to x-ray analysis of solid tissue will further our knowledge concerning transport properties in the kidney and …