Digital Commons Network^™

Direct Visualization And Silver Enhancement Of Ultra-Small Antibody-Bound Gold Particles On Immunolabeled Ultrathin Resin Sections, York-Dieter Stierhof, Bruno M. Humbel, Rene Hermann, Max T. Otten, Heinz Schwarz

Scanning Microscopy

Ultra-small gold colloids bound to immunolabeled ultrathin resin sections were visualized using transmission, scanning, and scanning transmission electron microscopy (TEM, SEM, STEM). The best marker contrast is obtained in a field emission STEM (200 kV) equipped with a high-angle annular dark-field (HAADF) detector. HAADF STEM renders possible the simultaneous visualization of ultra-small gold and ultrastructural details in unstained resin sections, and an overall presentation of a labeled E. coli cell.

For routine work, an enhancement step is a prerequisite for easy detection of bound marker molecules. Five different silver enhancing solutions were tested for their suitability for ultra-small gold intensification. …

Scanning Electron Microscopy Of Nerve Fibers In The Dog Cochlea, Hirofumi Morita, Tomoyuki Hoshino, Kunihiro Mizuta

Scanning Microscopy

The nerve fiber arrangement inside the organ of Corti in the dog was studied. Thick sections were cut serially from celloidin-embedded cochleas and observed with a scanning electron microscope (SEM). The nerve fibers in the organ of Corti were clearly exposed in sections cut in the horizontal plane. The arrangement of nerve fibers in the dog showed considerable difference from that of other species. The tunnel basilar fibers in the dog curved basalward, and took a long longitudinal course to form a broad bundle in the center of the tunnel floor. This bundle has not been found in adult animals …

Microwear Studies Of Early African Hominid Teeth, Pierre-François Puech

Scanning Microscopy

Studies of microwear on fossil hominid teeth have become an important approach in paleoanthropology. Since there are very few samples of early hominids from East Africa with suitable teeth, this paper presents a review of the occurrence of some dental wear characteristics to provide a data base for reconstructing the diet of the early hominids.

Distinctive microwear features such as furrows, crenulations, stress lines and deep grooves, are interpretive tools that can be used in a biomechanical approach. Occurrence of the same dental microwear patterns in extant species with known dietary differences is indicative of foods that have probably been …

The Effect On The Ultrastructure Of Dental Enamel Of Excimer-Dye, Argon-Ion And Co2 Lasers, J. Palamara, P. P. Phakey, H. J. Orams, W. A. Rachinger

Scanning Microscopy

This study aimed to investigate the ultrastructural changes that occur in dental enamel irradiated with pulsed excimer-dye, continuous-wave (CW) argon-ion and CW CO2 lasers. The pulsed excimer-dye laser produced deep craters, rough damaged surfaces with underlying porosity and amorphous vitrified material. The vitrification of the enamel indicated that the temperature in these areas must have been al least in the range 1280 to 1600°C. The CW argon-ion laser irradiation produced a changed non-cratered surface with inter-crystalline porosity and a mixture of small and some large irregularly packed recrystallized enamel crystals. The CW CO2 laser produced shallow craters, surface crazing and …

Comparison Of Cryopreparation Techniques For Electron Probe Microanalysis Of Cells As Exemplified By Human Erythrocytes, Karl Zierold

Scanning Microscopy

Erythrocytes in human blood were used to evaluate the reliability of cryopreparation techniques for electron probe X-ray microanalysis of biological cells and tissues. The elemental content determined by X-ray microanalysis of ultrathin freeze-dried cryosections was found to be consistent with data known from the literature. Considerable redistribution of the intracellular elemental composition was found after freeze-substitution as well as after freeze-drying followed by resin embedding. Two conclusions are drawn from this study: 1. Erythrocytes in human blood are a suitable reference specimen for evaluation of specimen preparation techniques for microanalysis. 2. At present, freeze-dried cryosections are the most reliable specimen …

Information And Misinformation Regarding Ischemia Of Heart Muscle Tissue. The Cause Of Cell Death During Blood Reperfusion And Reactivation Of Heart Muscle Tissue After Prolonged Ischemia, Fritiof S. Sjöstrand

Scanning Microscopy

An electron microscopic study of heart muscle tissue exposed to six hours ischemia and prepared according to the low denaturation embedding technique revealed a structural modification confined to the mitochondrial cristae. The modification consisted of a removal of Krebs cycle enzymes from the cristae. Reperfusion of the ischemic tissue after four hours ischemia led to extensive breakdown of the mitochondrial structure and contractility could not be restored. However, when after six hours ischemia the ischemic tissue was reperfused with blood, the composition of which had been modified to stimulate mitochondrial function, no additional structural changes were observed and contractility was …

Spectrally Resolved Transmission Cathodoluminescence Evaluation Of Vertical Cavity Surface Emitting Lasers, S. Myhajlenko, M. Wong, J. L. Edwards Jr., G. N. Maracas, R. J. Roedel

Scanning Microscopy

We describe an inexpensive addition to an existing cathodoluminescence system: Spectrally resolved transmission cathodoluminescence (SRTCL). In this technique, we couple the light emerging from beneath the sample into a vacuum compatible fiber optic cable for spectral dispersion by a conventional spectrometer. This simple approach represents a new development in the area of cathodoluminescence characterization. This exploratory study describes the preliminary results of this effort. We have applied SRTCL to the evaluation of InGaAs quantum wells, grown by molecular beam epitaxy, in vertical cavity surface emitting lasers. Results thus far support the viability of the technique. We also discuss the difficulties …

Computer Aided Phase Determination By Electron Probe Microanalysis, P. Nagy

Scanning Microscopy

A measuring procedure and a computer program have been developed for energy dispersive microanalysis to study segregation properties of various bulk, polished samples (alloys and ceramics). A few hundred sampling points were selected at random or regularly forming a grid pattern on the surface of the sample. Energy dispersive spectra were stored and ZAF corrected, and the obtained concentrations were evaluated statistically. An IBM AT compatible computer was used to calculate concentration distribution functions of the elements present in the sample. In addition to the usual statistical values, several types of concentration distribution functions were calculated. The method was tested …

Morphological Study Of Gastric Lesions Developing In The Rat Under Several Damaging Conditions: Modifications Induced By Pretreatment With Zinc Acexamate, M. Luisa Bravo, Ginés Escolar, Carmen Navarro, Ramón Fontarnau, Oriol Bulbena

Scanning Microscopy

Lesions developing in the gastric mucosa of the rat after exposure to different gastric damaging agents (100 mg/kg aspirin, and 70% or 100% ethanol) were assessed by scanning electron microscopy. The severity of the lesions was quantified according to morphological criteria. Modifications in the severity of these lesions induced by pretreatment with zinc acexamate were also analyzed. The scanning electron microscope revealed that with the exception of absolute ethanol, which caused distinctive morphological features, lesions found under the different experimental agents shared a common pattern of progression. Ultrastructural lesions on surface epithelial cells preceded further alterations of parietal cells. After …

Electron Probe Microanalysis Of The Otolithic Membrane. A Methodological And Quantitative Study, J. A. López-Escámez, F. J. Cañizares, P. V. Crespo, A. Campos

Scanning Microscopy

The effect of tissue preparation on calcium and potassium weight percents in the otoconial layer in the utricle and saccule was studied in four groups of OF1 mice with electron probe X-ray microanalysis. Glutaraldehyde and freeze-drying, glutaraldehyde and air-drying, air-drying, and cryo-fixation and freeze-drying were compared. Ca and K changed significantly in the utricle depending on the method used (P < 0.001), and K changed significantly in the saccule (P < 0.001 ). We chose cryo-fixation with freeze-drying for the quantitative analysis of the otolithic membrane because this method provided the highest values of Ca and K with minimum loss of Ca and K . Microcrystalline salt standards mounted on scanning electron microscopy holders were used for the quantification of Ca and K by the peak-to-local-background (P/B) ratio method. The P/B ratio in standards with reproducible results, when plotted against weight percent, gave a straight line for Ca (r = 0.99, P < 0.001) and K (r = 0.98, P < 0.001). The Ca and K weight percents in otoconia showed similar frequency distributions in the utricle and saccule.

Arthropathies Associated With Basic Calcium Phosphate Crystals, Paul B. Halverson

Scanning Microscopy

Basic calcium phosphate (BCP) crystals refer to a family of crystals including partially carbonate substituted hydroxyapatite, octacalcium phosphate, and tricalcium phosphate. These crystals have been found in and around joints and have been associated with several forms of arthritis and periarthritis. Identification of BCP crystals remains problematic because of the lack of a simple, reliable analytic procedure. Methods currently in use include alizarin red S staining, labelled diphosphonate binding, scanning and transmission electron microscopy with energy dispersive X-ray microanalysis, X-ray diffraction, and atomic force microscopy. Periarthropathies associated with BCP crystals include calcific tendinitis and bursitis. Intra-articular BCP crystal deposition is …

Multiple Phosphate Positions In The Catalytic Site Of Glycogen Phosphorylase, Stephen R. Sprang, Neil B. Madsen, Stephen G. Withers

Biological Sciences Faculty Publications

The three‐dimensional structure of an R‐state conformer of glycogen phosphorylase containing the coenzyme‐substrate analog pyridoxal‐5′‐diphosphate at the catalytic site (PLPP‐GPb) has been refined by X‐ray crystallography to a resolution of 2.87 Å. The molecule comprises four subunits of phosphorylase related by approximate 222 symmetry. Whereas the quaternary structure of R‐state PLPP‐GPb is similar to that of phosphorylase crystallized in the presence of ammonium sulfate (Barford, D. & Johnson, L.N., 1989, Nature 340, 609–616), the tertiary structures differ in that the two domains of the PLPP‐GPb subunits are rotated apart by 5° relative to the T‐state conformation. Global differences among the …

The Mayfly Newsletter, Peter M. Grant

The Mayfly Newsletter

The Mayfly Newsletter is the official newsletter of the Permanent Committee of the International Conferences on Ephemeroptera.

Nuclear Dna Content Variation Within The Rosaceae, E. E. Dickson, K. Arumuganathan, Stephen Kresovich, J. J. Doyle

Faculty Publications

Nuclear DNA content has been estimated using flow cytometry for 17 species and eight cultivars of Malus and for 44 species of 29 other genera within the Rosaceae. Compared to other angiosperms, diploid genome sizes vary little within the family Rosaceae and within the genus Malus. C-values of genera within the subfamilies Spiraeoideae and Rosoideae are among the smallest of flowering plants thus far reported. In general, the Maloideae have the largest diploid genomes of the family, consistent with their higher chromosome numbers and presumed polyploid origin.

Fatigability And Blood Flow In The Rat Gastrocnemius-Plantaris-Soleus After Hindlimb Suspension, Kerry S. Mcdonald, M. D. Delp, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to test the hypothesis that hindlimb suspension increases the fatigability of the soleus during intense contractile activity and determine whether the increased fatigue is associated with a reduced muscle blood flow. Cage-control (C) and 15-day hindlimb-suspended (HS) rats were anesthetized, and either the gastrocnemius-plantaris-soleus (G-P-S) muscle group or the soleus was stimulated (100 Hz, 100-ms trains at 120/min) for 10 min in situ. In the G-P-S preparation, blood flow was measured with radiolabeled microspheres before and at 2 and 10 min of contractile activity. The G-P-S fatigued markedly at this stimulation frequency, and the …

Vascular Anatomy Of The Pig Kidney Glomerulus: A Qualitative Study Of Corrosion Casts, B. J. Moore, Kenneth R. Holmes, Lisa Xuemin Xu

Scanning Microscopy

Pig kidney glomerular vascular anatomy was studied by scanning electron microscopy of vascular corrosion casts. A generalized vascular architecture is presented to describe the pig kidney glomerulus based upon the observation of 3,800 vascular cast glomeruli. The relative simplicity of the pig glomerular vascular architecture has allowed the characterization of different vascular segments more completely than has been possible in other mammals. Based upon relationships to the afferent arteriole, a nomenclature and definition of primary, secondary, tertiary and anastomotic vessels is proposed for the distributing vessels comprising the glomerular tuft. The existence and formation of a large central hemispheric vessel …

Luminal Constrictions On Corrosion Casts Of Capillaries And Postcapillary Venules In Rat Exocrine Pancreas Correspond To Pericyte Processes, Seyedhossein Aharinejad, Peter Böck

Scanning Microscopy

The rat exocrine pancreas was studied as a model to demonstrate morphological features of different types of capillaries, using scanning electron microscopy of vascular corrosion casts and transmission electron microscopy of tissue sections. Two types of capillaries were discerned. The first type represents less undulated, slender, straight capillaries with numerous, shallow, circular or semilunar furrows on its cast's surface. In tissue sections, this type probably corresponds to non-fenestrated capillaries. The numerous grooves on its cast correspond to pericyte processes beneath the endothelial lining. The second type comprises capillaries of an undulated course and variable diameter with less numerous furrows. In …

Appearance Of Venous Sphincters In The Pulmonary Microvascular Bed Of Normotensive And Spontaneously Hypertensive Rats, Seyedhossein Aharinejad, Peter Böck

Scanning Microscopy

The appearance of pulmonary venous sphincters was studied in normotensive and spontaneously hypertensive rats using scanning electron microscopy of microvascular corrosion casts and transmission electron microscopy of tissue sections. Vascular casts were prepared either after lavage with Tyrode solution or after glutaraldehyde prefixation. Pronounced pulmonary venous sphincters were more frequently identified in spontaneously hypertensive rats as compared to corresponding circular indentations in normotensive rats. Tissue sections established venous sphincters in hypertensive animals as consisting of multiple layers of smooth muscle cells in the venous walls. We did not observe any autonomic nerve terminals in close proximity to these bundles of …

Methods For The Study Of Calcium Oxalate Crystallisation And Their Application To Urolithiasis Research, J. P. Kavanagh

Scanning Microscopy

Many methods have been used to study calcium oxalate crystallisation. Most can be characterised by changes in supersaturation during the experiment, which may increase, remain constant or decay. Their ability to quantify various aspects of crystallisation often reflects the extent to which nucleation, growth and aggregation can be measured independently, when two or three of these processes may be occurring simultaneously.

The mixed suspension, mixed product removal technique reaches a steady state supersaturation, is a good model for intrarenal crystallisation and allows both growth and nucleation rates to be measured. Using 92% urine and comparing control urines with samples from …

A Stimulus Timing Device For Capturing Fast Physiologic Events By Quick-Freezing, R. Nassar, J. R. Sommer

Scanning Microscopy

A timing device was designed that, in conjunction with an impact type of quick-freezing apparatus and an externally-triggerable stimulus generator, allows the application of an electrical stimulus to a muscle preparation at a selected time interval before quick-freezing and the measurement of the interval with submillisecond precision. This is needed for stopping fast physiological events in calcium release and excitation-contraction coupling and allows studying the morphological parameters (by freeze-fracture and freeze-substitution) and elemental distributions (by x-ray microanalysis) as a function of time after stimulation. The device should be adaptable for use with most equipment designed for quick-freezing electrically excitable tissue …

Histochemical Demonstration And Microanalysis Of Possible Calcium Binding Sites In The Enamel Organ Of Rat Incisors, Y. Takano

Scanning Microscopy

The rat incisors obtained from rats perfused with high-calcium solution containing 30 to 50 mM CaCl₂ were processed for rapid freeze/freeze-substitution and embedded in epoxy resin. GBHA staining, a histochemical staining for calcium, of unhydrously prepared sections revealed a large number of granular Ca-GBHA reactions in the enamel organ, most of which being located along the lateral plasma membranes of the ameloblasts. In the ameloblast layer, the reaction was negative in the presecretory stage, became intense in concert with the onset of enamel matrix formation, and remained so by the end of the transitional stage where the reaction gradually …

Coherent Strain And Clustering In Ge/Si Heteroepitaxy, Jeff Drucker

Scanning Microscopy

The Ge/Si heteroepitaxial system grows in the Stranski-Krastanov (layer + island) growth mode with an equilibrium intermediate layer thickness of 3 monolayers. Initially, coherent (dislocation free) islands form above the intermediate layer. These coherent islands relieve part of their lattice mismatch by elastic deformation of the layer + island + substrate system. After cluster growth, these islands may reach a critical radius above which it becomes energetically favorable for strain relief through the introduction of misfit dislocations. Particle size distributions generated from digitally acquired secondary electron images of Ge/Si(100) films grown in situ in an ultra-high scanning transmission electron microscope …

Development Of A Semi-Synthetic Medium Supporting Adherent Growth In Coagulase-Negative Staphylococci, Abbas Sadeghi

Dissertations and Theses

A semi-synthetic medium for use in determining adherent growth with Staphylococcus epidermidis and Staphylococcus saprophyticus was developed. Production of an adherent biofilm was dependent upon the presence of hematin in the growth medium. Clinical strains of Staphylococcus epidermidis were tested for production of an adherent biofilm in trypticase soy broth, the semi-synthetic medium and the hyperalimentary nutrient solution used in the neonatal hospital unit. An adherent biofilm was obtained when Staphylococcus epidermidis was cultured m hematin supplemented hyperalimentary solution. Growth in the hyperalimentary nutrient solution diluted with fetal calf serum showed the same growth rate as when the nutrient solution …

Interaction Of Nutrition And Infection: Effect Of Copper Deficiency On Resistance To Trypanosoma Lewisi, A. Crocker, Clarence Lee, Georgiana Aboko-Cole, C. Durham

Department of Biology Faculty Publications

The copper-deficient rat-trypanosome system was used to study copper deficiency in Sprague Dawley rats infected with Trypanosoma lewisi. Throughout the observational period, animals on the deficient diet had lower plasma and liver copper concentrations compared with complete and pair-fed animals. In all dietary groups, the food intake and body weight changes of rats inoculated with T lewisi showed significant increases over the noninoculated controls. The rate of these indices were significantly less in the copper-deficient animals compared with the animals fed complete diets. Copper-deficient and pair-fed control rats showed greater numbers of parasites than controls throughout the infection. The duration …

Habitat, Diurnal, And Tidal Effects On The Behavior Of Glaucous- Winged Gulls (Larus Glaucescens), Dean Pearson

Loma Linda University Electronic Theses, Dissertations & Projects

The objectives of this study were to determine the effects of habitat, time of day and tide on the behavior of Glaucous-winged gulls nesting on Protection Island, Jefferson County, Washington. During the period of March - June, 1991, more gulls were present in the colony and their rates of behavior were greater during the morning and evening hours than during midday.

Though gull numbers and their rates of behavior in the colony tended to increase with tidal cycle, a plateau in these numbers and rates consistently occurred between +0.3m to +1.2m above mean tide.

More intrusion and courtship-related activity occurred …

An Approach To Solid Phase Identification In A Ca-S-O System By Quantitative Energy Dispersive X-Ray Microanalysis, K. Wieczorek-Ciurowa, S. J. Sivonen, P. Kokkonen

Scanning Microscopy

Solid phases formed in the limestone sulphation reaction were identified by scanning electron microscopy with backscattered electron (BSE) imaging and by quantitative energy dispersive X-ray (EDX) microanalysis of calcium and sulphur. Since calcium and sulphur can form several compounds in the Ca-S-O system, two quantities, the sum of oxides (CaO+SO₃) and the molar ratio (CaO/SO₃), were used to calculate empirical formulae for the compounds actually present.

A method for analysing the experimental results is proposed, the mathematical expressions employed are presented and the numerical coefficients tabulated. It is shown with some examples that the method used …

Functional And Morphological Studies Of Mitochondria Exposed To Undecagold Clusters: Biologic Surfaces Labeling With Gold Clusters, E. Valdivia, C. Gabel, J. E. Reardon, C. A. Cajacob, H. Yang, R. S. Wehbi, G. L. Scott, P. A. Frey, L. A. Fahien

Scanning Microscopy

This study reports morphological and functional alterations observed in respiring isolated mitochondria when they are exposed to nonpenetrating, positive electrostatically charged synthetic undecagold clusters. Modification of the undecagold clusters positive charges change or prevent the functional effects and the binding to the outside surface of the mitochondria. The mitochondrial functional alterations are dependent on the oxidative phosphorylation capacity of the isolated organelles. The results of these experiments indicate that artificial undecagold may be useful to explore the molecular mechanisms of biological energy transducers which require electric charges separation, ionic fluxes, and electric surface properties.

Scanning X-Ray Microanalysis Of Microcarrier Cultured Endothelial Cells: Elemental Changes During The Transition To Confluency And The Effect Of Ionophore A23187, S. R. Hall, D. C. Sigee, J. E. Beesley

Scanning Microscopy

Porcine endothelial cells were grown on microcarrier beads and examined by scanning electron microscopy (SEM) at various times after initiation of culture. Total cell coverage on the bead surface varied from mean values of approximately 7% (3h) to 80% (96h). Beam penetration into the subcellular matrix presents a major problem with SEM X-ray microanalysis of microcarrier cultured cells and necessitates the use of an accelerating voltage not exceeding 10kV. At this voltage and below, X-ray contribution from elements present in the microcarrier bead has minimal effect on the determination of cell elemental levels. Washing the cells with 0.15M sucrose was …

Ua66/6/2 Bionews From The Hill, Wku Biology

WKU Administration Documents

Newsletter created by and about WKU Biology highlighting the activities of faculty, students and alumni.

Synthesizing Embryology And Human Genetics: Paradigms Regained, Scott F. Gilbert

Biology Faculty Works

No abstract provided.