Digital Commons Network^™

Tandem Scanning Reflected Light Microscopy, Mojmir Petran, Milan Hadravsky, Alan Boyde, Martin Mueller

Scanning Electron Microscopy

Most attempts at optical microscopy of bulk living objects have failed because of reflections from optical components and the object surface, and overlapping of unsharp out-of-focus images with the one (weak) sharp in-focus image. The optical signal in the image plane thus consists of a strong d.c. component, a weak noise and a still weaker signal. Most of the first two components can be suppressed by scanning in concordance with both the illuminating and the image-forming rays. In the first scan the focussed-on-object plane is illuminated only in several very fine discrete spots. In the second scan only that light …

Cryofixation And Cryosubstitution For Routine Work In Transmission Electron Microscopy, H. Sitte, K. Neumann, L. Edelmann

Scanning Electron Microscopy

After a brief review of the present state of the theory of cryofixation, methods and instruments as well as criteria for the application of cryofixation and cryosubstitution in daily routine work in cell biology and medicine are described. Good results are obtainable using liquid nitrogen for impact freezing on highly polished copper surfaces or by plunging into liquefied propane. Based on these results a versatile and safe system for routine plunging and impact freezing for the majority of biomedical objects has been developed. In order to enable ultramicrotomy at ambient temperature a cryosubstitution system according to the Edelmann principle has …

Cryopreparation Of Tissue For Electron Microscopy, John G. Linner, Stephen C. Bennett, Donna S. Harrison, Alton L. Steiner

Scanning Electron Microscopy

An apparatus able to remove amorphous phase tissue water without recrystallization or rehydration has been produced. Application of this technique to biological samples achieves both the preservation of ultrastructure and the retention of cellular macromolecules and solute without redistribution or modification.

Small pieces of fresh tissue were cryofixed by the method of bounce free metal-mirror freezing on polished copper bars at liquid nitrogen temperature. Tissue samples were then placed under liquid nitrogen in a copper sample holder equipped with a thermocouple and feedback controlled heating circuit. Under liquid nitrogen the sample block was placed in a stainless steel sample chamber …

Theoretical Study Of Anomalously High F Region Peak Altitudes In The Polar Ionosphere, Jan Josef Sojka, Robert W. Schunk

All Physics Faculty Publications

During the last solar maximum period several observations of anomalously high F region peak altitudes have been made by the high latitude incoherent scatter radars. The observations indicate that there are several distinctive features associated with these high h_mF₂ ionospheric profiles: (1) they are observed near midnight with the plasma flowing out of the polar cap, (2) N_mF₂ ranges from 105 to 106 cm−3, (3) h_mF₂ ranges from 400 to 500 km, (4) below 300 km the profile is devoid of ionization, and (5) the observations are for solar maximum conditions. …

A Theoretical Study Of The Global F Region For June Solstice, Summer Maximum, And Low Magnetic Activity, Jan Josef Sojka, Robert W. Schunk

All Physics Faculty Publications

We constructed a time-dependent, three-dimensional, multi-ion numerical model of the global ionosphere at F region altitudes. The model takes account of all the processes included in the existing regional models of the ionosphere. The inputs needed for our global model are the neutral temperature, composition, and wind; the magnetospheric and equatorial electric field distributions; the auroral precipitation pattern; the solar EUV spectrum; and a magnetic field model. The model produces ion (NO⁺, O₂⁺, N₂⁺, N⁺, O⁺, He⁺) density distributions as a function of time. For our …

Proceedings From The 22nd Annual Marschall Invitational, Various Authors

Cheese Industry Conference

No abstract provided.

Preliminary Geologic Map Of The Nephi 30' By 60' Quadrangle, Carbon, Emery, Juab, Sanpete, Utah, And Wasatch Counties, Utah, United States Geological Survey

All U.S. Government Documents (Utah Regional Depository)

The U.S. Geological Survey is engaged in a program of field studies designed to present the geologic framework of the United States on easily read topographic maps. The maps selected as a base for these geologic data are part of the Army Map Service (AMS) series of 1° by 2° quadrangles at a scale of 1:250,000. The Price, Utah AMS 1:250,000 quadrangle is one of these maps (fig.1). For certain areas, however, chiefly those sectors of the country involved in the Geological Survey's coal exploration program, the geologic data are being compiled on newly developed base maps at a scale …

Bedrock Aquifers Of Eastern San Juan County, Utah, United States Geological Survey

All U.S. Government Documents (Utah Regional Depository)

This study is one of a series of studies appraising the water-bearing properties of the Navajo Sandstone and associated formations in southern Utah. The study area is about 4,600 square miles, extending from the Utah-Arizona State line northward to the San Juan-Grand County line and westward from the Utah-Colorado State line to the longitude of about 109 degrees 50 minutes.

Holiday Bread 'Round The World, Flora Bardwell

Archived Food and Health Publications

Booklet gives a variety of recipes for Holiday Breads from different countries and cultures.

Coniferous Forest Habitat Types Of Central And Southern Utah, U.S. Forest Service

All U.S. Government Documents (Utah Regional Depository)

A habitat type classification for the coniferous forests of central and southern Utah includes the heirarchical taxonomic system of land classification that is based on potential natural vegetation of forest sites and uses data from more than 720 sample stands

Predicting Duff And Woody Fuel Consumed By Prescribed Fire In The Northern Rocky Mountains, United States Department Of Agriculture, Forest Service

Forestry

This paper presents numerical relationships of known precision for predicting duff consumption. They were established by assembling and analyzing data from three previous prescribed fire investigations and then testing them against other published data. Fuel loadings by diameter classes that differed among the studies were converted to a common set of diameter classes. The purpose of assimilating data from several studies was to develop predictive models that could be easily used by practitioners and that would apply over a wide range of conditions.

Woodland Tree Volume Estimation: A Visual Segmentation Technique, United States Department Of Agriculture, Forest Service

Forestry

Visual segmentation, a technique for estimating cubic foot volume of woodland tree species, was compared with actual volume measurement. Comparison was made during a forest inventory of pinyon-juniper woodlands in Nevada and Utah. The visual technique's accuracy, its usefulness in developing volume equations, and applicability to volume inventory were studied. This study indicated visual segmentation is not reliable for estimating volume for a single tree. However, a sample of visually estimated volumes proved adequate for developing volume equations. In an application, a bias of 0 to -9 percent of the mean cubic foot volume per acre resulted from summary of …

Measurement Of Field Resistance, Rust Hazard, And Deployment Of Blister Rust-Resistant Western White Pine, United States Department Of Agriculture, Forest Service

Forestry

Three white pine plantations, composed of materials of several levels of resistance from early generations of the blister rust resistance breeding program, were compared on the basis of annual infection and mortality rates. The sites varied in blister rust hazard; resistant materials were consistent in their performance, and the infection data behaved as one would expect if the genetic and environmental assumptions of the simple interest disease progress model were violated. Presumably, the resistant populations violate the genetic assumptions to the extent of their resistance, and any assessment of resistance performance must take into account both environmental as well as …

Release Of A Thinned Budworm-Infested Douglas-Fir/Ponderosa Pine Stand, United States Department Of Agriculture, Forest Service

Forestry

Current and past defoliation by western spruce budworm (Choristoneura occidentalis Freeman) in an 80-year-old predominantly Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) stand thinned to 14 by 14 feet was significantly lower than in a nearby untreated stand of similar age, species, and site conditions. Analysis of periodic radial growth ratios indicated that prior to thinning, Douglas-fir had been heavily defoliated by budworm and growth was seriously depressed. Following thinning, the host leave trees developed dense crowns and 10-year radial growth increased an average of 57 percent: meanwhile, radial growth of nonhost ponderosa pine (Pinus ponderosa Dougl.) increased 38 percent. …

Costs Of Managing Nontimber Resources When Harvesting Timber In The Northern Rockies, United States Department Of Agriculture, Forest Service

Forestry

When National Forest Timber is sold, land managers are required to protect other forest resources such as wildlife, soil and water, and scenic qualities. Measures taken to protect nontimber resources can raise administrative costs, lower the quantity of timber sold, and can reduce stumpage receipts. The costs of sale administration and the reduction in timber harvested can be readily derived from accounting and planning records. But little information is available on how much nontimber resources cost in terms of stumpage receipts. To provide such information, some 187 timber sales were studied on seven National Forests in the Northern Region between …

Applying Height Growth And Site Index Curves For Inland Douglas-Fir, United States Department Of Agriculture, Forest Service

Forestry

Methods for estimating both site index and dominant height growth for inland Douglas-fir in the Northern Rocky Mountains are presented and discussed. The methods should be applicable over a wide range of stand conditions because no restrictions were placed on species composition, stand density, spacing, or age structure in the original stem analysis sample. Increased accuracy can be obtained if habitat type is considered, because the shape of the site index curves varied with respect to three major habitat series groupings. Results are summarized in the form of equations, tables, and graphs. Precision curves are used to illustrate the relationship …

Effects Of Bifenox, Dcpa, And Napropamide On Ectomycorrhizal Development Of Conifer Seedlings In Central And Northern Rocky Mountain Nurseries, United States Department Of Agriculture, Forest Service

Forestry

Postseeding and postgermination treatments with three weed control herbicides (Bifenox, DCPA, Napropamide) at two rates of application caused little reduction of ectomycorrhizal development on 1- and 2-year-old conifer seedlings in Central or Northern Rocky Mountain nurseries. In many cases, herbicide treatment increased ectomycorrhizal development, particularly with DCPA. In general, herbicide treatment effects on ectomycorrhizal development were species and nursery specific.

Pinyon-Juniper Volume Equations For The Central Rocky Mountain States, United States Department Of Agriculture, Forest Service

Forestry

Gross cubic foot volume equations are now available for pinyon-juniper and several other woodland species in Nevada, Idaho, Utah, Colorado, Wyoming, and South Dakota. The volume equations are based on data collected as a subsample of woodland inventories conducted by Federal and State land management agencies. In these inventories, volumes of 4,705 trees were estimated by a visual sampling method.

The Delphi Method: Application To Elk Habitat Quality, United States Department Of Agriculture, Forest Service

Wildlife Conservation and Management

This paper reports on the results of a study designed both to gather important information through Delphi and to evaluate several key features of the Delphi process. We intend to present information developed, and also describe and discuss Delphi so as to make resource managers more comfortable with it, aware of its potential, and willling to consider it along with other information gathering tools.

Refilling Of Geosynchronous Flux Tubes As Observed At The Equator By Geos 2, Jan Josef Sojka, G. L. Wrenn

All Physics Faculty Publications

During periods of extended quiet geomagnetic activity the geosynchronous satellite orbit lies inside the plasmasphere. Five such periods were observed by the GEOS 2 satellite. During the initial 48 hours of such periods the equatorial plasma flux tube density increases at 30 to 50 cm⁻³/day. However, on reaching ∼100 cm⁻³ the refilling rate decreases, and refilling is limited. Only when the density reaches ∼100 cm⁻³ do the plasma characteristics and fluctuations appear to be plasmaspheric and the flow predominantly corotational. The “hot outer zone” of the plasmasphere is highly structured in density and temperature when viewed …

Lecture 10: Staying A Student Of Trees And People As Your Hair Turns Grey, J. J. Kennedy

Last Lectures

No abstract provided.

The State Of Water In The Cell, William Negendank

Scanning Electron Microscopy

A number of scientists in the early 20th century conceived cell water and ions as existing in unique "colloidal" or "bound" states. Work in the 1930's, however, established the assumption that most of cell water and of K exist in a free state like that of a dilute aqueous solution, so that the osmotic activity of cell K serves to balance that of the high concentration of extracellular Na. This assumption underlies theoretical concepts of membrane pumps, Donnan equilibria, and cell potentials, and led to the now classical membrane-osmotic-pump-leak concept of cell ionic distributions and volume maintenance. Nevertheless, the results …

Demonstrable Fixative Interactions, Keith M. Meek, John A. Chapman

Scanning Electron Microscopy

Electron-optical examination of reconstituted collagen fibrils fixed with tannic acid and/or glutaraldehyde and positively stained with heavy metal anions and cations reveals distinct changes in the high resolution staining patterns seen in TEM. Correlation with the known sequence data demonstrates that these changes are caused by (a) interaction of the fixative with certain charged groups in the collagen and (b) localized stain-exclusion effects following fixation. We have analysed the positive and negative staining patterns from glutaraldehyde-treated collagen in detail. In positive staining, uptake of staining ions is shown to be inhibited not only at residues known to interact with glutaraldehyde …

Observation Of Colloidal Gold Labelled Platelet Surface Receptors And The Underlying Cytoskeleton Using High Voltage Electron Microscopy And Scanning Electron Microscopy, R. M. Albrecht, J. A. Oliver, J. C. Loftus

Scanning Electron Microscopy

Fibrinogen conjugated to colloidal gold or colloidal gold-monoclonal anti-glycoprotein IIb/IIIa (fibrinogen receptor) was used to label the receptor on platelets. Whole mount preparations were examined by stereo pair high voltage electron microscopy and then by scanning electron microscopy to determine the feasibility of this approach in detecting the number of receptors and their location relative to the cytoskeletal and surface structure. Both the ligand-gold and antibody-gold labels were effective. The relative numbers of receptors could be seen and their relationship to cytoskeletal structure could be determined. Marked differences in receptor number and distribution were observed when platelets in different stages …

Cell Volume Regulation Studies With The Electron Microprobe, Mary Jo Ingram, F. Duane Ingram

Scanning Electron Microscopy

Lumbricals from the hind feet of young rats are dissected free, stretched to approximately 125% of resting length, and mounted on individual, simple plastic forms. After recovery in physiological saline, the isolated muscles are incubated for periods of 40 to 60 min. in one of a series of hypertonic bathing solutions. The composition of each bathing solution is identical, except for osmolality which is increased with lactose. At least one muscle from each animal is incubated in a control solution to serve as a control muscle for that particular set of 5 to 8 muscles. Mounted muscles are removed from …

Does The Embedding Chemistry Interact With Tissue?, B. E. Causton

Scanning Electron Microscopy

Resins and resin compounds interact with tissue in two ways, physico-chemically and by chemical reaction. The physico-chemical influences affect both the structure and biological activity of the tissue causing proteins to change shape or phase equilibria to be disrupted by a change in solvent or by the growth of polymer networks within existing biological polymeric structures. Chemical reactivity between tissue and resin components also reduces biological activity by changing either the structure of polymeric matter already present, e.g., crosslinking proteins, grafting hydrophobic resins onto hydrophilic protein backbones, or by modifying the hydrophobicity of specific sites, e.g., acylation of amino groups …

Two Opposing Theories Of The Cell: Experimental Testing By Cryomethods And Electron Microscopy, L. Edelmann

Scanning Electron Microscopy

A main controversial issue in cell biology concerns the molecular mechanism responsible for K⁺ accumulation in living cells and Na⁺ exclusion from them. The alternative theoretical descriptions of these phenomena are based on different assumptions about the physical state of cellular Na⁺, K⁺ and H₂O. In this article it is shown with striated muscles how cryomethods and microanlytical electron microscopy may be used to test the opposing theories. It is concluded that these methods may yield more realistic informations about the physical state of cellular K⁺ and Na⁺ than measurements with …

Complementary Replicas Of Ultra-Rapidly Frozen Specimens, M. J. Costello, R. D. Fetter, T. G. Frey

Scanning Electron Microscopy

Complementary freeze-fracture replicas have been prepared of ultra-rapidly cooled specimens in the absence of chemical pretreatments. The grid-sized replicas were stabilized by open mesh gold grids during the cleaning process and, after cleaning, were supported on thin Formvar films. The complementary replicas were valuable for describing artifacts, for interpreting the nature of fracture planes and for evaluating the resolution of replicas. Complementary images demonstrated that heat emitted from resistance electrodes or electron guns during evaporation can seriously distort fracture surfaces even for samples held at -150°C. Complementary images of crystalline membranous cytochrome c oxidase helped establish that fracturing reveals hydrophilic …

The Glass Knife In Ultramicrotomy, Lahja Sevéus, Cecilia Tarras-Wahlberg

Scanning Electron Microscopy

To obtain the best ultrathin sections in ultramicrotomy and cryoultramicrotomy, a high quality knife is of paramount importance. Glass knives were introduced for ultramicrotomy, in the manually broken form, in 1950. Since the introduction of mechanical knifemakers, the production of glass knives has become a standardized laboratory routine. In conventional ultramicrotomy different knife angles are used to cover different specimens and embedding media. The 50° knife broken with a small deviation of the score from the diagonal of the square gives a long useful edge, especially if damping during breaking is used. The 50° knife is, therefore recommended as the …

Low Temperature Embedding, E. Carlemalm, W. Villiger, J. -D. Acetarin, E. Kellenberger

Scanning Electron Microscopy

The Lowicryl resins K4M and HM20 are methacrylate/acrylate based formulations which can re used for embedding biological material at low temperature in conjunction with either the progressive lowering of temperature (PLT) technique or with freeze-substitution. The resins are applicable over a very extended temperature range, approximately 210°K to 340°K. Even lower temperatures down to ca. 190°K can be reached with two new resins, K11M and HM23. Test embeddings of unfixed material after freeze-substitution have given promising results which could re useful for imnunocytochemical labeling. Lipid extraction is small or absent when the two new resins are used in combination with …