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A New Approach To Low Temperature Embedding: Quick Freezing, Freeze-Drying And Direct Infiltration In Lowicryl K4m, R. Chiovetti, S. A. Little, J. Brass-Dale, L. J. Mcguffee

Scanning Electron Microscopy

Lowicryl resins are most commonly used for low temperature embedding by progressively lowering the temperature during dehydration. Freeze-substitution has also been successfully used with Lowicryl, but both of these techniques generally rely on chemical fixation and prolonged incubations in organic solvents. Freeze-drying may be combined with embedding in Lowicryl K4M. This technique eliminates all chemical fixation and exposure to organic solvents since the samples are quick-frozen, dried in vacuo and directly infiltrated in pure Lowicryl resin. If a primary aldehyde fixation is desired, freeze-drying may be used as an alternative to dehydration with organic solvents. These new approaches may be …

Freeze Substitution And Low Temperature Embedding, B. Humbel, M. Müller

Scanning Electron Microscopy

The problems of conventional EM-preparation techniques based on chemical fixation may be overcome to a considerable extent by freeze substitution techniques. Although at present substitution cannot be performed at sufficiently low temperatures to prevent the recrystallization of vitrified aqueous specimens, thin sectioned biological samples show an improved information density. If freeze-substitution is combined with conventional embedding above 273 K (Epon/Araldite, Spurr's resin) the substituting organic solvent must contain stabilizing agents such as osmiumtetroxide, glutaraldehyde or uranylions. In combination with low temperature embedding procedures (Lowicryl) completely unfixed samples are obtained, which are suitable for immunolabelling and electron spectroscopic experiments. Water in …

Colloidal Gold Particles Detected On Highly Structured Surfaces Of Large Samples By Backscattered Electrons In The Scanning Electron Microscope, D. Studer, R. Hermann

Scanning Electron Microscopy

Colloidal gold labelled surface antigens on large, highly structured samples were unambiguously visualized at high magnification with backscattered electrons at 25 kV in a field emission scanning electron microscope (SEM). Secondary electron (SE) and backscattered electron (BSE) images of large and highly structured specimens are frequently disturbed by charging effects. By optimizing the thickness of the conducting carbon layer and the intensity of the incident electron beam, this problem can be overcome. The midgut of the lepidopteran larvae of Spodoptera litoralis was used as specimen. The activated 𝛿-endotoxin of Bacillus thuringiensis coupled to colloidal gold binds to the microvilli exposed …

To Resin Or Not To Resin In Immunocytochemistry, J. J. Wolosewick

Scanning Electron Microscopy

Hydrated resinless sections produced by a variety of methods (cryoultramicrotomy or polyethylene glycol techniques) appear to be excellent specimens for post-embedding immunocytochemistry at the electron microscopic level. A perplexing problem is the lack of apparent penetration throuqhout the section thickness of particulate probes such as ferritin or colloidal gold. This report draws attention to the possible causes for this phenomenon namely the size of the probe and the possible effects of fixation or processing. Smaller probes, gentler fixation or permeabilization procedures and increased incubation times all seem to be logical approaches to increasing penetration of immunoreagents into thick hydrated sections.

Immunocytochemical Labeling Of Enzymes In Low Temperature Embedded Plant Tissue: The Precursor Of Glyoxysomal Malate Dehydrogenase Is Located In The Cytosol Of Watermelon Cotyledon Cells, C. Sautter

Scanning Electron Microscopy

The Lowicryl-technique in combination with protein A gold was used in order to localize the precursor of glyoxysomal malate dehydrogenase in watermelon cotyledons. Preservation of the antigen was evaluated by a preembedding technique in isolated organelles. The glyoxysomal malate dehydrogenase was localized in tissue sections by a postembedding technique. Antigens of glyoxysomal malate dehydrogenase were found in the glyoxysomal matrix and in the cytosol, whereas the endoplasmic reticulum was completely free of labeling. Controls are presented by preimmunserum, by a serum against various proteins of the glyoxysomal membrane and by application of cycloheximide in order to inhibit translation at cytosolic …

Detection Of Small (5-15nm) Gold-Labelled Surface Antigens Using Backscattered Electrons, Paul Walther, Martin Müller

Scanning Electron Microscopy

The analysis of surface antigens by scanning electron microscopy represents a practicable alternative to replica techniques. It is generally observed that smaller markers provide for better labelling. In the SEM very small colloidal gold labels however are hardly discerned from contaminants or from surface structures of similar size. They are however unambiguously demonstrated by combining the surface information provided by the secondary electron signal and the material dependent signal provided by the backscattered electrons. A field emission SEM equipped with a highly sensitive single crystal backscattered electron detector allows the routine detection of 5 nm gold particles on biological surfaces. …

The Morphology Of Thin Metal Coatings Formed By Rotary Shadowing Biological Species In High Vacuum, J. A. Panitz

Scanning Electron Microscopy

Rotary Shadowing has been used to increase the image contrast of biological species observed during edge-projection imaging in the transmission electron microscope. In this imaging mode, biological species are adsorbed from aqueous solutions onto a highly curved substrate and viewed, over its edge, in a direction parallel to its surface. Since the substrate is not placed between a biological adsorbate and the photographic emulsion that records its image, any material can be used as a support (including high-Z metals and semiconductors). Binding to these technologically interesting materials is observed with unusual clarity and contrast, even at 200kV. Individual adsorbates and …

Plasma Membrane Antigens Detected By Replica Techniques, H. Hohenberg, W. Bohn, G. Rutter, K. Mannweiler

Scanning Electron Microscopy

Methods are introduced for in situ preparation of cell cultures grown on glass coverslips using the replica technique. Special equipment and handling procedures enabled us to prepare large-sized and stable replicas suitable for ultrastructural and immunocytochemical analysis of the different faces of the plasma membrane (PM): the extraplasmic surface (ES), the complementary extraplasmic (EF) and protoplasmic (PF) fracture face, and the protoplasmic surface (PS). Colloidal gold markers in combination with protein A and monospecific/monoclonal antibodies were used to identify virus-specific antigens at the ES of infected cells. Stereo replicas show a coincident location of gold-labeled virus antigens at the ES …

High Resolution Scanning Electron Microscopic Cytology - Specimen Preparation And Intracellular Structures Observed By Scanning Electron Microscopy, T. Inoué

Scanning Electron Microscopy

With the recent developments of the specimen preparation techniques, intracellular organization has been observed three-dimensionally by scanning electron microscopy (SEM). A suitable preparation method is the most important factor for observing intracellular structures at high resolution. Since intracellular structures are usually hidden in the cytoplasmic matrix, SEM observation of them is impossible merely by cracking the fixed cell. To remove the fixed cytoplasm, an osmic maceration technique is the most effective method which is applicable to almost all kinds of specimen preparation. In our laboratory, we developed some methods for observing intracellular structures. Those are the O-D-O method, the A-O-D-O …

Human Metaphase Chromosome Preparation For Scanning Electron Microscopy - A Consideration Of Inherent Problems, T. D. Allen, E. M. Jack, C. J. Harrison, D. Claugher, R. Harris

Scanning Electron Microscopy

Although the physical dimensions of chromosomes are such that they fall well within the spatial resolving power of scanning electron microscopes, results in the past have been disappointing. This is most likely due to limitations in preparative techniques, coupled with the initial necessity to separate the chromosomes from the remainder of the metaphase cell. Two approaches have been employed, a; to use a variety of isolation buffers which provide bulk chromosome preparations, b; to use metaphase spreads prepared essentially as for light microscopy and re-processed for SEM. In the former, wide variations in chromosome surface topography and fibre organisation arise …

Working At Higher Magnifications In Scanning Electron Microscopy With Secondary And Backscattered Electrons On Metal Coated Biological Specimens And Imaging Macromolecular Cell Membrane Structures, Klaus-Ruediger Peters

Scanning Electron Microscopy

Membrane structures of macromolecular dimensions were imaged with high resolution secondary electron type I (SE-I) signal contrasts on metal coated biological specimens. The quality of the surface information was strongly dependent on the signal used for microscopy and on the properties of metal films, i.e., thickness, continuity, structure and decoration effects. Films of 10 nm thickness produced so much type II electrons that identical images were obtained with the conventional SE-II and BSE-II signals. In such images, the type I SE signal was so low that only very weak contrasts were recognizable. If the films - continuous or discontinuous - …

Undergraduate Research And Creative Opportunities Directory Accounting Through Utah Water Research Laboratory, Utah State University

Undergraduate Research Office

Summarizes URCO and showcases some students and their projects. Explains process and how to apply for funding if needed. Contains list of current research projects at the university.

Undergraduate Research And Creative Opportunities Directory Animal, Dairy, & Veterinary Sciences Through Administration Vp Business, Utah State University

Undergraduate Research Office

Summarizes URCO and showcases some students and their projects. Explains process and how to apply for funding if needed. Contains list of current research projects at the university.

The Roll Away Saloon, Rowland W. Rider

All USU Press Publications

With his animated tales of Zane Grey, Butch Cassidy, and the Robbers Roost gang, Rider creates an engaging and believable picture of the joys and hardships of cowboy life.

Preparation Of Cryosections For Biological Microanalysis, Karl Zierold

Scanning Electron Microscopy

The element distribution in biological cells and tissues can be revealed by electron probe microanalysis from ultrathin cryosections. In particular, the distribution of physiologically important and often mobile elements such as Na, Mg, P, S, Cl, K, and Ca can be studied in cryosections on an ultrastructural level. The cryopreparation technique required for this purpose consists of 1. cryofixation, 2. cryosectioning, 3. cryotransfer including freeze-drying and carbon coating if necessary, 4. energy dispersive X-ray microanalysis in a cold stage equipped scanning transmission electron microscope. The lateral analytical resolution of this method is less than 50 nm in freeze-dried ultrathin (about …

Problems Associated With The Preparation Of Cell Suspensions For X-Ray Microanalysis Highlighted By The Comparison Of Results With Those Obtained From Tissue Sections, A. Warley, M. D. Kendall, I. W. Morris

Scanning Electron Microscopy

Fully quantitative X-ray microanalysis of freeze dried frozen sections allowed the concentration of monovalent ions in the nuclei of mouse thymocytes in tissue sections to be compared with those from thymocytes which had been isolated by a simple preparation procedure. Isolated cells showed increased concentrations of Na and Cl. This was further investigated in the rat where the size of the thymus a 11 owed comparison between different isolation media using cells derived from the same animal. Use of autologous serum as the final suspending medium gave reproducible results, whereas with suspension in BSS, or 20% dextran the results were …

Immuno-Cytochemistry With Backscattered Electrons, D. Soligo, E. De Harven, M. T. Nava, G. Lambertenghi-Deliliers

Scanning Electron Microscopy

Some cytochemical reaction products are visible inside the cytoplasm of cells observed with the scanning electron microscope (SEM) using the backscattered electron imaging (BEI) mode. Methods can be utilized whenever they result in the deposition of heavy metal, like silver, lead or osmium at the sites of the enzymatic reaction.

More recently the BEI mode of the SEM has been demonstrated to improve the detection of immunogold labeled cell surface antigens. Colloidal gold particles, 40 to 15 nm in diameter can be efficiently used for immuno-specific labeling. Moreover, cytochemical reactions can be applied to previously immunogold labeled cells, therefore combining …

A Review And Evaluation Of The "Appraisal Report Estimating Fair Market Rental Value Of Public Rangelands In The Western United States Administered By Usda - Forest Service And Usdi - Bureau Of Land Management", Darwin B. Nielsen, E. Bruce Godfrey

Economic Research Institute Study Papers

The use of rangelands administered by agencies of the federal government by domestic livestock has been an issue associated with controversy for many years. One of these issues that has surfaced periodically has been the fees charged livestockmen who use lands administered by the Bureau of Land Management (BLM) and Forest Service (FS). This issue became politically "hot" in 1977 and 1978. This controversy became intense enough that Congress established a fee formula as part of the Public Rangelands Improvement Act (PRIA) of 1978. Congress directed that this formula be used during a seven-year trial period. It was further stipulated …

Vacant Federal Grazing Allotments In The West, E. Bruce Godfrey, Darwin B. Nielsen, Denny Lytle

Economic Research Institute Study Papers

It has been surmised in recent years that there are a growing number of vacant grazing allotments on federally administered land. Increasing costs and decreasing returns have forced many livestock producers out of the business. Growing demands for recreational areas have resulted in an increased number of conflicts between ranchers and other users of public land. For these and a variety of other reasons, many allotments that were formerly grazed are now vacant. Thi s paper examines the acreage, number of AUMs, and some of the implications of vacant grazing allotments in the West.

Historic Resource Study Bryce Canyon National Park, Nicholas Scrattish

Elusive Documents

No abstract provided.

Canopy Architecture Of A Red Maple Edge Stand Measured By A Point Drop Method, D.R. Miller, J.D. Lin

Aspen Bibliography

No abstract provided.

Sexual Reproduction, Seeds, And Seedlings In Aspen: Ecology And Management In The Western United States, W.T. Mcdonough

Aspen Bibliography

Natural genetic interchange and extensive colonization of aspen by seed strongly depends upon favorable climatic and microclimate conditions and upon human intervention.

Water And Watershed In Aspen: Ecology And Management In The Western United States, Norbert V. Debyle

Aspen Bibliography

No abstract provided.

Wood Resource In Aspen: Ecology And Management In The Western United States, J.R. Jones, N.V. Debyle, R.P. Winokur

Aspen Bibliography

Aspen has not been cut extensively in the West; in fact, it has been grossly underutilized. For example, as recently as 1975, the aspen harvest from National Forests in four Forest Service regions in the Rocky Mountain area was 7.64 million board feet.¹ Additional minor volumes were cut on special-use permits for products such as fuel and corral poles. The total amount cut represented only 0.1% of the net volume available in these aspen forests.

Rotations In Aspen: Ecology And Management In The Western United States, J.R. Jones, W.D. Shepperd

Aspen Bibliography

The rotation, in forestry, is the planned number of years between formation of a crop or stand and its final harvest at a specified stage of maturity (Ford-Robertson 1971).

Vegetation Associations In Aspen: Ecology And Management In The Western United States, Walter F. Mueggler

Aspen Bibliography

Aspen trees grow along moist stream bottoms as well as on dry ridges and southerly exposures, on talus slopes, and on shallow to deep soils of varied origins. Quaking aspen is one of the few plant species that can grow in all mountain vegetational zones from the alpine to the basal plain (Daubenmire 1943). As a consequence, aspen dominated communities are found intermixed with such divergent vegetation as semiarid shrublands and wet sprucefir forests

Effects Of Chemical Weed Control And Seedling Planting Depth On Survival And Growth Of Aspen, G.L. Reighard, G. Howe, J.W. Hanover

Aspen Bibliography

No abstract provided.

Effect Of The Interplanetary Magnetic Field Y Component On The High‐Latitude Nightside Convection, O. De La Beaujardiere, Vincent B. Wickwar, J D. Kelly, J H. King

All Physics Faculty Publications

Sondrestrom radar observations reveal that the dawn‐dusk (B_y) component of the interplanetary magnetic field (IMF) strongly influences the nightside polar convection. This effect is quite complex. The convection for one orientation of B_y is not the mirror image of the other orientation. A positive B_y (i.e., pointing toward dusk) seems to organize the velocities such that, at all local times, they are predominantly westward within the radar field‐of‐view (≃68°‐to‐82° invariant latitude). Between dusk and midnight, on one such occasion, sunward flow is observed within the polar cap. In the midnight and dawn sectors, when B_{y …}

Journal Of Mormon History Vol. 12, 1985

Journal of Mormon History

• --Without Purse of Scrip? Financing Latter-day Saint Missionary Work in Europe in the Nineteenth Century

Richard J. Jensen, 3

• --Change Engulfs a Frontier Settlement: Ogden and Its Residents Respond to the Railroad

Brian Q. Cannon, 15

• --Religion and Culture: A Persistent Problem

Langdon Gilkey, 29

• --Entre Nous: An Intimate History of MHA

Maureen Ursenbach Beecher, 43

• --John E. Page: An Apostle of Uncertainty

John Quist, 53

• --The Earliest Reference Guides to the Book of Mormon: Windows into the Past

Grand Underwood, 69

• --John Hafen and the Art Missionaries

Martha Elizabeth Bradley and Lowell M. Durham, Jr., 91

NOTES, …

Utah Science Vol. 46 No. 4, Winter 1985

Utah Science

112 THE BIG ROCK CANDY MOUNTAIN F. B. Salisbury A researcher who has periodically studied the unusual mountain over a period of three decades says the mountain has not yet yielded all of its secrets. And photographs indicate that while natural change appears to occur slowly, the face of the mountain can be altered in a few hours by heavy rainfall.

119 NEW GRASSES FOR INTERMOUNTAIN RANGELANDS K. H. Asay, W. H. Horton and W. T. Hansen II Researchers are developing several productive grasses, even some which promise to capitalize on the desirable attributes of quackgrass.

124 DEATH RATES AND …