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Effects Of Ambient Lake Mohave Temperatures On Development, Oxygen Consumption, And Hatching Success Of The Razorback Sucker, Michael A. Bozek, Larry J. Paulson, Gene R. Wilde

Publications (WR)

Spawning of razorback suckers, Xyrauchen texanus, in Lake Mohave occurred from 10-22° C and larvae were collected at water temperatures from 10-15° C in 1982 and 1983. In the laboratory, hatching success was similar from 12-20° C, but reduced hatching success was found at 10° C while none hatched at 8°C. Development rate and oxygen consumption were positively related to incubation temperature. Direct effects of ambient Lake Mohave water temperatures on hatching success of razorback sucker embryos are considered minimal. Historical spawning temperatures for the species are hypothesized based upon successful incubation temperatures and comparison to the white sucker, …

Factors Related To The Occurrence Of Certain Prairie Graminoid Species In Black Hawk County, Iowa, Roadsides, Pauline Mary Drobney

Dissertations and Theses @ UNI

The native vegetation of Iowa was primarily tallgrass prairie and currently exists only in small isolated parcels, including some remnants occurring in roadsides. Roadside prairie remnants are important for historical, environmental, aesthetic, scientific, and economic reasons. Information about factors influencing the occurrance of roadside prairie vegetation could be useful to roadside vegetation managers in development of initial vegetation surveys and subsequent to restoration of roadside prairie vegetation.

This study was conducted to determine what factors most affected the percent coverage of prairie graminoids in roadsides; particularly soil moisture availability, drainage, soil disturbance, and availability of a prairie seed sources. Prairie …

Microbial Production And Consumption Of Nitrate In An Annual Grassland, John M. Stark, E. A. Davidson, M. K. Firestone

Biology Faculty Publications

Gross nitrification rates (calculated by 15N pool dilution) ranged from 12 to 46% of gross mineralization rates during the growing season of annual grasses. Pools of NH4+ and NO3 (measured as N) remained below 7 and 4 ,ug/g soil, respectively, but turned over about once a day. Microbial assimilation of NO3- occurred at rates similar to previous estimates of plant uptake. Hence two common assumptions, that nitrifying bac-teria are poor competitors for NH4+ and that microbial immobilization of NO3- is insig-nificant, are not correct for this grassland system. Soil heterogeneity probably results in NH4+ availability to NH4+ oxidizers at some …

The Second Indian River Research Symposium Foreword, Ned P. Smith, Richard L. Turner

Ocean Engineering and Marine Sciences Faculty Publications

No abstract provided.

Isolation And Analysis Of The Nitrate Reductase Structural Gene From Squash, Cucurbita Maxima, David Joseph Bryk

Master's Theses

No abstract provided.

Regulation Of Gonadotropins By Steroids In Isolated Rat Pituitary Cells, Lenette L. Renier

Master's Theses

No abstract provided.

Transcriptional Regulation Of Gene Expression In Tetrahymena Thermophila, Laurie A. Stargell, Kathleen M. Karrer, Martin A. Gorovsky

Biological Sciences Faculty Research and Publications

The only well-characterized study of gene expression in Tetrahymena thermophila (1) demonstrates that the temperature dependent expression of the Ser H3 gene is regulated at the level of mRNA stability. A run-on transcription assay was developed to determine if regulation of RNA stability was a major mechanism regulating gene expression in Tetrahymena or if transcriptional regulation dominates. The relative transcriptional activities of 14 Tetrahymena genes were determined in different physiological/developmental states (growing, starved and conjugating) in which many of the genes showed striking differences in RNA abundance. In every case except Ser H3, changes in transcription accompanied changes in RNA …

Ua66/6/3/1 Biennial Report, Kentucky Gamma, Alpha Epsilon Delta

Student Organizations

Biennial report created by and about the Kentucky Gamma Chapter of Alpha Epsilon Delta premedical honor society sponsored by WKU Biology.

Quantitative Evaluation Of Scanning Electron Microscopy-Examined Ciliary Morphological Changes In Control And Noise Exposed Guinea Pig Cochleas, S. Rydmarker, P. Nilsson, D. E. Dunn, C. Lindqvist

Scanning Microscopy

Many investigations of noise-induced hearing loss have demonstrated a poor correlation between hearing threshold and hair cell loss. One reason for this is that more subtle changes in the hair cell, such as detailed morphological changes of stereocilia, have not been evaluated. However, examining such changes increases the problem of distinguishing experimental pathological changes from artefacts. Preparation of the specimen for scanning electron microscopy (SEM) may result in too many artefacts for an adequate quantification of defects due to noise exposure.

One problem with some earlier studies seems to be lack of controls and/or statistical analysis for the purpose of …

Calcium Pyrophosphate Crystal Deposition: A Kinetic Study Using A Type I Collagen Gel Model, Gretchen S. Mandel, Paul B. Halverson, Melisa Rathburn, Neil S. Mandel

Scanning Microscopy

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by deposits of triclinic (t) and monoclinic (m) CPPD crystals in articular and fibrocartilage. Many investigators have attempted to model CPPD crystal growth using both solution and a variety of gel systems. We have investigated the effect of type I collagen fibrils on CPPD crystal nucleation and growth using an ionic diffusion model. Collagen was isolated from porcine menisci using a pepsin solubilization procedure and gelled in three layers, with one containing 10 mM pyrophosphate (PPi) plus physiologic ions, the middle containing only the ions, while the third contained 25 mM …

The Secondary Blood Vessel System Of Segmental Arteries And Dorsal Aorta In Blennius Pavo And Zosterisessor Ophiocephalus. Histology, Fine Structure And Sem Of Vascular Corrosion Casts., F. Lahnsteiner, A. Lametschwandtner, R. A. Patzner

Scanning Microscopy

The secondary blood vessel system of the segmental arteries and of the dorsal aorta of the teleost fish Blennius pavo and Zosterisessor ophiocephalus are examined by light microscopy, transmission electron microscopy and by scanning electron microscopy of appropriately processed tissue and of vascular corrosion casts. Dorsal, lateral and ventral segmental arteries and the caudal portions of the dorsal aorta have a secondary vessel system. The secondary vessels are formed by capillaries which arise from the proximal portions of the segmental arteries and from the caudal parts of the dorsal aorta. In Z. ophiocephalus these capillaries are strongly dilated at their …

Backscattered Electron Imaging Of Partially-Demineralized Enamel, D. G. A. Nelson

Scanning Microscopy

Backscattered electron (BE) microscopy is being used increasingly as a technique to study the dissolution of dental enamel because of its high resolution and relatively easy sample preparation. Subsurface details such as striae of Retzius, cross-striations and prism microstructure have been observed with a resolution better than 0.1 micrometers using this technique. Since BE images of demineralized enamel appear very similar to microradiography images, it is tempting to interpret them in a similar fashion. We attempt to show that the interpretation of BE images is not straightforward because enamel is not a homogeneous one-phase material, but a two-component composite material …

Binding Of Ions To Nuclear Chromatin, Thomas Von Zglinicki, Heiko Ziervogel, Martina Bimmler

Scanning Microscopy

Ion concentrations in isolated lymphocyte nuclei subjected to KCl or MgCl₂ media of varying ionic strength were measured by X-ray microanalysis. Values were corrected for the contribution of free ions by estimating the volume fraction of the water space morphometrically. The amount of bound cations and Cl was constant and independent of the widely varying free ion concentration.

It is concluded that the mechanism of binding is counterion condensation but with limited cooperativity. In contrast to classical counterion condensation theory, the binding of ions occurs at oppositely charged clusters at the surface of the chromatin. Therefore, both cations and …

Effectiveness Of Dentin Bonding Agents, J. -F. Roulet, U. Blunck

Scanning Microscopy

The interface between a composite resin restoration and dentin is still a problem with regard to secondary caries and esthetics. With conventional restorative techniques the absence of bonding between the restorative material and the dentin produces marginal gaps. These gaps are populated with microorganisms or trap pigments. Therefore, adhesive techniques are required for functional and esthetic restorations.

In extracted teeth stored in 0.1% thymol solution, 8 cylindrical cavities (diameter: 3 mm; depth: 2 mm) and 8 class V cavities (1/2 of the margin in dentin) were prepared in each group and filled with composite resin. Before actual placement the following …

Electron Microscopy Of Endothelial Cell - Biopolymer Interaction, Stuart K. Williams, Timothy Schneider, Bruce E. Jarrell

Scanning Microscopy

Vascular endothelial cells form a natural antithrombogenic lining on all blood vessels. Replacement or bypass of small diameter blood vessels with artificial polymeric grafts has not been clinically acceptable due to the thrombogenic nature of polymeric material. One approach to improving the patency of vascular prosthetic devices has been the establishment of endothelial monolayers on the blood flow surface using the technique known as seeding. Scanning electron microscopy has been a major tool in evaluating the interaction of endothelial cells with polymeric surfaces resulting in a basic understanding of forces and structures regulating endothelium-polymer interactions. In-vitro and in-vivo studies have …

Comparison Of Backscattered Scanning Electron Microscopy And Microradiography Of Secondary Caries, Grayson W. Marshall Jr., Michal Staninec, Yasuhiro Torii, Sally J. Marshall

Scanning Microscopy

Carious lesions are usually studied using light microscopy and/or microradiography which require preparation of thin sections. Backscattered scanning electron microscopy (BSEM) has received little attention although it provides information similar to that obtained with microradiographs, with the potential for higher resolution. Recently, microscopes have been introduced that can be used to study wet or nonconducting specimens, offering techniques for studying specimens without desiccation or preparation of thin sections. This investigation sought to determine if secondary carious lesions have the same characteristics when studied by microradiography as when using the "wet" BSEM mode. Microradiographs were made of thin sections from restored …

The Use Of Scanning Electron Microscopy In The Analysis Of Pathological Hairs, Bo Forslind

Scanning Microscopy

The potentials of the scanning electron microscope (SEM) have only to a certain degree been exploited in the study of pathological hair fibers. In this review brief viewpoints on aspects of preparation and interpretation are discussed. It is shown that SEM will reveal important facts on the morphology of pathological hairs is appropriate experiment are performed, such as forming a knot on the fiber. Such a simple experiment will provide information on the fiber cross section, and on the tensile strength of the cuticle and the fiber. Complementary methods for qualitative and quantitative analysis of pathological hair fibers are suggested.

Release Of Hemoglobin And Potassium From Human Red Blood Cells Treated With Triton X-100 Under The Critical Micellar Concentration, P. Bogner, M. Kellermayer, C. F. Hazlewood

Scanning Microscopy

The action of detergents is thought to be connected primarily with micelle formation. However, detergent monomers can also effect biological systems. It was found in this study that human red blood cells can be disintegrated with Triton X-100 non-ionic detergent at a concentration of 0.007 %, lower than the critical micellar concentration (CMC). The time dependent release of hemoglobin and potassium was detected at 37°C and both were sigmoid in character. Although potassium was released faster than hemoglobin, a cooperative relationship between potassium and hemoglobin within the intact red blood cell is suggested by this observation.

Properties Of A New Dental Porcelain, T. K. Vaidyanathan, J. Vaidyanathan, A. Prasad

Scanning Microscopy

A high strength dental porcelain OPTEC, HSP™ has recently been introduced for use in the fabrication of crowns, three-unit anterior bridges with a single pontic, inlays, on lays, veneers, etc., without a metal substrate. This investigation reports the results of our research involving the characterization of the structure properties and thermally induced transformations of this porcelain. It has been found that the material possesses superior strength and other properties relative to conventional porcelains. The improved properties appear to result from the presence of a very fine and relatively dense distribution of leucite crystals. Scanning electron microscopy indicates, however, that the …

Ultrastructural Features Of Osteoclasts In Situ, L. De Saint-Georges, S. C. Miller, B. M. Bowman., W. S. S. Jee

Scanning Microscopy

The morphology of in situ osteoclasts on endocortical surfaces of the femoral midshaft was examined by scanning electron microscopy. Mice were perfusion fixed and bone marrow plugs were flushed out of femoral diaphyseal cylinders. The bones were split longitudinally and the endocortical surfaces examined. This method left on the bone surface most of the endosteal cells in their natural, in situ shape and position. Most of the bone surface was lined by contiguous bone lining cells covering resting bone surfaces, making a clear physical barrier between the bone and marrow compartments. On resorption surfaces, which were characterized by excavation cavities, …

Non-Fibrous Inorganic Particles In Human Bronchoalveolar Lavage Fluids, P. Dumortier, P. De Vuyst, J. C. Yernault

Scanning Microscopy

Bronchoalveolar lavage (BAL) is a simple and non-invasive sampling technique of the deep lung. Analytical electron microscopy was used for the identification and quantification of non-fibrous inorganic particles recovered in BAL fluid samples from 51 subjects with various occupational exposures (silica, silicates, metals and alloys, metallic oxides, precious and hard metals, abrasives). Around 4750 particles were analysed. More than sixty different compounds were identified, among which silica, kaolinite, illite, mica, Fe oxides and hydroxides, appeared to be ubiquitous. Feldspar, talc, chlorite, Al oxide, Ti oxide, tungsten carbide, stainless steel, carbonaceous compounds and flyash were also frequently encountered. From 1 to …

Studies Of Heart Development In Normal And Cardiac Lethal Mutant Axolotls: A Review, M. E. Fransen, L. F. Lemanski

Scanning Microscopy

The morphology of developing hearts in axolotls, Ambystoma mexicanum, has been studied by scanning electron microscopy in order to provide a chronology of morphogenesis that can be correlated with ongoing biochemical and immunocytochemical studies. In addition to normal embryos we have studied homozygous recessive cardiac lethal mutant axolotls. The mutant myocardium undergoes aberrant sarcomere development and lacks a normal heartbeat. Morphogenesis of mutant hearts appears to be nearly normal with respect to myocardial cell shape changes, epicardial formation, and the distribution of extracellular matrix fibrils in the cardiac jelly. This suggests that the deficient arrangement of contractile proteins in …

Cryofixation Of Heart Tissue For X-Ray Microanalysis, Alice Warley

Scanning Microscopy

Cryofixation of tissues is necessary to be able to study the concentrations of elements by X-ray microanalysis. Simple dissection of heart tissue fragments of the size needed for optimum cryofixation by the conventional methods of plunge or slam freezing leads to the development of ischaemia in the tissue fragments and a consequent redistribution of the diffusible elements. Heart tissue can be frozen in vivo using liquid nitrogen cooled Cu clad pliers, but the morphological detail is preserved better if the cooled pliers are exposed to liquefied propane immediately before freezing, Concentrations of Na are lower and concentrations of K are …

An Analytical Method Of Determining Thickness Of Multi-Layer Films With Electron Microprobe, Yen-Cai Ho, Jia-Guang Chen, Xin-Lei Wang

Scanning Microscopy

In the previous work we have developed a series of theoretical corrections for calculating the emitted X-ray intensity in multi-layer films. By the use of these theories, along with careful experimental operation of the electron probe microanalysis (EPMA) and Monte Carlo iteration calculation, the thickness of each layer in multi-layer films can be determined.

To test the reliability of this method, the multi-layer film specimens Au/Cu/Si, Cu/Au/Si and Ag/Cr/Si of known thicknesses were analyzed at 20, 25, 30 and 35 keV. The percentage relative errors between the thicknesses determined using the correction procedures and those measured using nuclear backscattering are …

Interferon Beta 2/Interleukin-6 And Interleukin-3 Synergize In Stimulating Proliferation Of Human Early Hematopoietic Progenitor Cells., R. Michalevicz, D. Lifshitz, M. Revel

Scanning Microscopy

Early 4-hydroxyperoxycyclophosphamide (4-HC) resistant hematopoietic progenitor cells (pre-colony-forming units, pre-CFU) were evaluated by a two-step liquid culture system, (earlier progenitors), pre-CFU, as well as by the conventional semi-solid mixed colony assay (later progenitors) for their growth response to interleukin-6 (IL-6), interleukin-3 (IL-3), and a combination of both factors. The effect of the IL-6/IL-3 combination was compared to that of IL-1/IL-3. IL-3 alone proved less effective in supporting earlier pre-CFU cells than later progenitor cells. In a previous work IL-6 promoted the growth of early multipotential progenitor cells circulating in hairy cell leukemia (HCL) patients. IL-6 alone did not stimulate growth …

Bone Ingrowth Into Porous Coated Canine Total Hip Replacements. Quantification By Backscattered Scanning Electron Microscopy And Image Analysis, Murali Jasty, Charles R. Bragdon, Steven Schutzer, Harry Rubash, Teresa Haire, William H. Harris

Scanning Microscopy

Bone ingrowth into titanium fiber mesh porous-surfaced canine total hip replacement prostheses was evaluated and quantified using a computer assisted image analysis system attached to a scanning electron microscope equipped with a back scattered electron detector. Excellent contrast between the bone, the porous metal and the soft tissues resulted in the backscatter mode, allowing easy differentiation of these components in real time by the image analysis based on gray scales. By three weeks the mean (± standard deviation) amount of bone ingrowth expressed as a percentage of porous layer measured 7.2% (± 1.5%) for the acetabular components, and 3.9% (± …

Site-Directed Mutagenesis Of The Putative Processing Site Of Recombinant Human Immunodeficiency Virus Reverse Transcriptase, Susan M. Poppe

Masters Theses

The human immunodeficiency virus (HIV) is the etiological agent of the acquired immune deficiency syndrome (AIDS). This retrovirus, encodes a RNA dependent DNA polymerase, reverse transcriptase (RT), which is essential to virus replication. Biochemical analysis indicated that RT is composed of 2 polypeptides of 66,000 and 51,000 daltons (p66 and p51) which combine to form a heterodimer. This heterodimer is thought to arise from the post-translational processing where p66 is made and either autocatalytic or proteolytic cleavage events result in a heterogeneous p66/p51. Site-directed mutagenesis was used at the proposed processing site to probe HIV-RT processing.

Three prokaryotic expression vectors …

Introduction And Enhancement Of Vegetative Cover At Lake Mead, Jennifer S. Haley, Lisa K. Croft, Suzanne E. Leavitt, Larry J. Paulson

Publications (WR)

Studies done by the Nevada Department of Wildlife (NDOW) and the Arizona Fish and Game between 1978 and 1981 indicate that inadequate cover may be limiting the production and survival of largemouth bass at the Lake Mead National Recreation Area (LMNRA). As a result of these studies, NDOW initiated a contract in 1986 with the Lake Mead Research Center (LMRC) to investigate means of improving habitat for game fish by introducing natural and/or artificial cover. During Phase I (1986-1987) of this contract, the shoreline of Lake Mead was surveyed for aquatic and terrestrial plant growth. Also during this time, submerged …

Achilles Tendon Replacement By A Collagen Fiber Prosthesis: Morphological Evaluation Of Neotendon Formation., Arthur J. Wasserman, Y. Pedro Kato, David Christiansen, Michael G. Dunn, Frederick H. Silver

Scanning Microscopy

Reconstituted type I collagen was processed into fibers which were subsequently severely dehydrated and cyanamide cross-linked. Fibers prepared by this method were stronger and more resistant to degradation than uncrosslinked fibers. When used as a tendon replacement prosthesis, morphological events occurred which were observed by light, scanning, transmission electron microscopy and electron histochemistry.

Resorption was the initial host response to the prosthesis and involved gradual biodegradation. Formation of a host-replacement tendon was the second response. Increased collagen fibril diameters and a transition in the proteoglycan/collagen fibril interactions occurred in the newly developing connective tissue between 3 and 10 weeks post-implantation. …

Analytical Description Of X-Ray Peaks: Application To L X-Ray Spectra Processing Of Lanthanide Elements By Means Of The Electron Probe Micro-Analyzer, G. Remond, Ph. Coutures, C. Gilles, D. Massiot

Scanning Microscopy

The shape of Lα X-ray peaks analyzed by means of a LiF (200 plane) monochromator was described by a pseudo-Voigt function:

P(λ) = 0.35 P₁(λ)+ 0.65 P₂(λ)

where P₁(λ) and P₂(λ) are a Gaussian and a Lorentzian distribution centered at the same wavelength, with the same amplitude and half-width and in relative proportion 0.35 and 0.65 respectively. For peaks occurring at wavelength greater than ≃ 0.17 nm, a Gaussian offset was added in order to correct the asymmetry of peaks resulting from the monochromator mounting within the spectrometer.

The effective wavelength resolution …