Life Sciences Commons^™

Calcospherites In Rabbit Incisor Predentin, H. Mishima, Y. Kunuki, T. Sakae, Y. Kozawa, N. Watabe

Scanning Microscopy

Calcospherites from the lower incisor dentin of rabbits were investigated by scanning and transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and electron diffraction analyses. In the labial predentin, globular calcospherites of 8-31 μm were present at the root apex, decreasing in size toward the incisal region. The calcospherites at the intermediate region were of mulberry- as well as of spindle-shape of 1.5-4 μm diameter. The incisal pulp horn contained micro-calcospherites of 0.3-0.6 μmin diameter. In the lingual predentin, small granular calcospherites of 1. 8-3 μm were present at the root apex, increasing in size toward the intermediate region. Ultrathin …

Present Developments In Image Analysis, Peter Smart, Xiaoling Leng

Scanning Microscopy

The paper discusses novel methods of analysing oriented textures, explains some of the problems which had to be overcome to make these methods work, and indicates where future developments might be expected. This has required improvements in the methods of intensity gradient analysis, the development of large filter methods for mapping features defined in terms of their texture, and the introduction of ideas from the theory of regionalised variables.

Ultra-High Resolution Scanning Electron Microscopic Studies On The Sarcoplasmic Reticulum And Mitochondria In Various Muscles: A Review, Takuro Ogata, Yuichi Yamasaki

Scanning Microscopy

The three-dimensional structure of the sarcoplasmic reticulum (SR), transverse (T)-axial tubular system and mitochondria in various muscles was examined by means of ultra-high resolution scanning electron microscopy (SEM) after removal of the cytoplasmic matrices and myofilaments by the aldehyde-osmium-DMSO-osmium procedure. The striated muscles reviewed and presented are twitch and slow fibers of the frog, twitch and slow fibers of the chicken, twitch extrafusal fibers and intrafusal fibers of the rat, and cardiac muscle fibers of the rat and dog. In all of these striated muscle fibers, T-tubules run transversely and are coupled with terminal cisternae forming triads or dyads. Sarcotubules …

Influence Of Annealing On The Interface Structure And Strain Relief In Si/Ge Heterostructures On (100) Si, D. J. Lockwood, J. -M. Baribeau, T. E. Jackman, P. Aebi, T. Tyliszczak, A. P. Hitchcock, R. L. Headrick

Scanning Microscopy

Research work on the general problem of the nature and thermal stability of the Si/Ge semiconductor interface is reviewed. We report on our recent studies of the interface structure in [(Si)_m(Ge)_n]_p superlattices and (Ge)_n layers buried in Si as revealed by Raman scattering, extended X-ray absorption fine structure, and X-ray techniques. Strain relaxation and interdiffusion in the superlattices caused by annealing have been investigated, and it is found that considerable strain-enhanced intermixing together with partial relaxation of Ge-Ge bonds occurs even for very short anneal times at 700°C. Further annealing leads to diffusion at …

Strain Distribution During Growth Of Ge/Si(001) And The Effect Of Surfactant Layers, J. E. Macdonald, J. M. C. Thornton, A. A. Williams, P. Ashu, C. C. Matthai, H. A. Van Der Vegt, E. Vlieg

Scanning Microscopy

Grazing incidence X-ray diffraction has been employed to determine directly the distribution of strain in the plane of the interface during deposition of Ge onto Si(001). The corresponding strain distribution has also been deduced for a relaxed island whose atomic structure has been determined by molecular dynamics. The results illustrate the central role of elastic deformation of islands in the initial stage of strain relief. The results are also compared with those for growth with a Sb surfactant layer which suppresses island formation. An investigation of surfactant-like behaviour is also presented for homoepitaxial growth of Ag on Ag(111), where sub-monolayer …

Electron Beam Lithography For Large Area Patterning 3: Data Conversion And Electron Beam Deflection Control, Susumu Hoshinouchi, Hiroaki Tobuse, Hidenobu Murakami, Ryuichi Shimizu

Scanning Microscopy

Electron beam direct writing technologies, specifically for the large area patterning of electronic devices such as printed wiring boards, are studied in this paper. The vector scanning method with two kinds of beam deflection, main-deflection and sub-deflection, has been adopted for the fabrication of circuit patterns of various line widths. The sub-deflection of high frequency oscillation is superimposed on the main-deflection, which allows for controlling each line width with ease. A data conversion and a deflection control system with several strategies have been developed to reduce the conversion time and the volume of output data. It is revealed that circuit …

Electron Beam Lithography For Large Area Patterning 4: Exposure Of Resist On Internal Surface Of A Through-Hole, Susumu Hoshinouchi, Akio Yoshida, Hidenobu Murakami

Scanning Microscopy

Electron beam direct writing technologies, specifically for the large area patterning of electronic devices such as printed wiring boards, are studied in this paper. The exposure characteristics of the resist on the internal surface of a through-hole are examined. A thick film resist which is composed mainly of unsaturated acrylic resins is prepared on the internal surface of the hole by an electrodeposition process.

It is proven that a 20 μm thick resist on the internal surface can be exposed efficiently by a 60 keV electron beam. This phenomenon becomes even stronger by placing a gold plated metal plate on …

A Scanning Electron Microscopic Study Of The Chick Chorioallantoic Membrane: Cell Death And The Involvement Of Oxygen Free Radicals, A. Easterling, G. J. Burton, J. N. Skepper, M. H. Nasr-Esfahani

Scanning Microscopy

Cell death is a normal feature within the chick chorioallantoic membrane, occurring principally between days 10 and 14 of incubation.

Samples of chorioallantoic membrane were obtained on days 6, 8, 10, 12 and 14 of incubation, after the creation of artificial air chambers on day 3. These were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) after staining for acid phosphatase activity, and by light microscopy after demonstrating oxygen free radicals with nitro blue tetrazolium. On day 6, small defects in the plasmalemma, approximately 200 nm in diameter, could be seen by SEM. A sequence of events leading …

Denitrification And Oxygen Consumption In Sediments Of Two South Texas Estuaries, Won Bae Yoon, Ronald Benner

Faculty Publications

Spatial and temporal variations in rates of denitrification and oxygen consumption were measured in sediments of the Nueces and Guadalupe Estuaries in southern Texas, USA. Denitrification rates varied from 4.0 to 71.1 µmol N₂ m^-2 h^-1 in the Nueces Estuary and from 4.6 to 34.7 µmol N₂ m^-2 h^-1 in the Guadalupe Estuary. Denitrification accounted for 29 to 80% of total benthic N flux in the study areas. Oxygen consumption rates ranged from 176 to 818 µmol O₂ m^-2 h^-1 in Nueces Estuary and from 208 to 550 µmol O_{2 …}

X-Ray Microanalysis Of Epithelial And Secretory Cells In Culture, Anne Von Euler, Eva Pålsgård, Christina Vult Von Steyern, Godfried M. Roomans

Scanning Microscopy

Cell cultures can be used to study ion transport processes. X-ray microanalysis of cell cultures at the cellular level gives interesting information that can complement electrophysiological and tracer studies. In this paper, methods for culturing and preparing a variety of epithelial and secretory cells (fibroblasts, insulinoma cells, bovine mammary epithelial cells, colon cancer cells) for X-ray microanalysis are presented. Results show that sometimes cell cultures are not homogeneous with respect to ion content or reaction to physiological stimuli. In colon cancer cell cultures, a "high K" and a "low K" cell subpopulation was found; these subpopulations also differed with respect …

Ultrastructural Features Of Human Reissner's Membrane, Anne De Fraissinette, Heidi Felix, Jannie Nievergelt, Michael Gleeson

Scanning Microscopy

Ultrastructural features of human Reissner' s membrane were investigated in two groups of similarly aged patients. Five patients had age-related normal hearing (ARNH) and four patients had acquired sensorineural hearing loss (SNHL) from causes other than age. The membrane consisted of a mesothelium facing the perilymph and an epithelium facing the endolymph. The two cell layers were separated by a basement membrane. The mesothelium was formed by wide spread thin cells with a smooth surface. The epithelial cells assumed two different shapes, flat and rounded. Both epithelial cell types were covered with many short microvilli. In all specimens, the rounded …

Microvascular Architecture Of The Filiform Papillae In Primates And Insectivores, S. Okada, Y. Ohta, N. Matsukawa, S. Sugioka

Scanning Microscopy

The microvascular architecture of filiform papillae was investigated under a scanning electron microscope in man, Japanese monkeys, common squirrel monkeys, common marmosets, common tree shrews, large Japanese moles and dwarf shrews utilizing microvascular corrosion casts. Filiform papillae were circularly arranged in primates, and each of them was supplied by a hairpin capillary loop. These papillae sometimes were aggregated. The filiform papillae of Japanese monkeys exhibited markedly locational differences on the lingual dorsum and were supplied by circularly arranged capillary loops or by an intrapapillary capillary network. Small filiform papillae were located on an epithelial eminence in the lingual radix, each …

Recent Advances In Measurement Of Oxalate In Biological Materials, S. Sharma, R. Nath, S. K. Thind

Scanning Microscopy

Hyperoxaluria is the predominant risk factor in urinary stone disease. A specific, accurate and reliable oxalate assay for urine and plasma is very important for both the diagnosis and efficient management of patients. A review of the advantages and disadvantages of various methods of oxalate determination is presented and is followed by the authors' recommendations.

High-Resolution Scanning Electron Microscopy Of Rat Incisor Ameloblasts, A. Nanci, S. Zalzal, F. W. K. Kan

Scanning Microscopy

The internal three-dimensional organization of secretory and maturation stage ameloblasts was examined using field emission scanning electron microscopy. Particular attention was given to the structure of the Golgi apparatus, the distribution of smooth membrane tubulo-vesicular elements and their relationship with endosomal/lysosomal components. Rat incisors were fixed by intracardiac perfusion with glutaraldehyde, decalcified and divided into segments. The tissues were cryoprotected with glycerol and freeze-fractured. They were then macerated in osmium, and after conductive staining with osmium/tannic acid, the samples were critical-point dried and sputtered with gold. High-resolution scanning electron microscopy showed that ameloblasts contain a well-developed Golgi apparatus, even in …

Distribution Of Connectin (Titin) And Transverse Tubules At Myotendinous Junctions, Y. Shimada, F. Atsuta, M. Sonoda, M. Shiozaki, K. Maruyama

Scanning Microscopy

The ends of muscle fibers form many longitudinal projections which are further divided into numerous processes and attach to the collagen fibrils of tendons to form myotendinous junctions (MTJs). Immunocytochemical and electron microscopic observations on pectoralis muscles of the chicken revealed the presence of an elastic filamentous protein, connectin (titin), within the terminal sarcomere on the side adjacent to the terminal Z bands, and the absence of connectin and myosin and the presence of actin at the apical sarcoplasmic region of MTJ processes between the terminal Z band and the MTJ sarcolemma. Intermediate voltage electron microscopy showed that T tubules …

The Nucleation And Growth Of Calcium Oxalate Monohydrate On Self-Assembled Monolayers (Sams), Allison A. Campbell, Glen E. Fryxell, Gordon L. Graff, Peter C. Rieke, Barbara J. Tarasevich

Scanning Microscopy

A physical chemical approach was used to study calcium oxalate monohydrate (COM) nucleation and growth on various organic interfaces. Self-assembling monolayers (SAMs), containing derivatized organic functional groups, were designed to mimic various amino acid residues present in both urine and stone matrix macromolecules. Derivatized surfaces include SAMs with terminal methyl, bromo, imidazole, and thiazolidine-carboxylic acid functional groups. Pronounced differences in COM deposition were observed for the various interfaces with the imidazole and thiazolidine surfaces having the greatest effect and the methyl and bromo groups having little or no nucleating potential.

The Use Of Sonic Frequencies As A Cleaning Agent Of Specimens To Be Observed By Scanning Electron Microscopy, G. Familiari, A. Familiari, G. Macchiarelli, L. J. A. Didio, P. M. Motta

Scanning Microscopy

The presence of mucus and/or cellular debris can obscure the fine morphology of the gastrointestinal or respiratory luminal surface, when observed by scanning electron microscopy. With the intent of obtaining a good cleaning of the mucosal surface without altering the ultrafine morphology of epithelial cells, a new model of sonicator/ultrasonicator is presented.

The instrument is supplied with a control system for wave frequency, amplitude and form, and permits a precise regulation of the wave energy. With this instrument it is possible to produce a "cleaning effect" by using any kind of frequency (either sonic or ultrasonic) and/or amplitude and/or waveform …

Influence Of 17-B-Estradiol And Progesterone On The In Vitro Cultured Mouse Preimplantation Embryos, Matthew L. Offutt

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Matthew L. Offutt on December 10, 1992.

Cellular Interactions In Hemopoietic Progenitor Cell Homing: A Review, Cheryl L. Hardy, Jose J. Minguell

Scanning Microscopy

Within the bone marrow microenvironment, dynamic cellular interactions are constantly occurring. These interactions involve hemopoietic stem cells, progenitor cells and maturing cells, physically interacting with other cells, some of which may function as accessory cells, and others which comprise the stromal elements; hemopoietic cells also interact with non-cellular elements, such as glycoproteins and fibrous proteins of the extracellular matrix (ECM). These interactions serve to regulate normal hemopoiesis by allowing the communication of regulatory information, migration and subsequent homing of stem cells within specific organs, and presentation of hemopoietic growth factors in a biologically relevant fashion. The goal of this review …

Bacterial Numbers And Activity, Microalgal Biomass And Productivity, And Meiofaunal Distribution In Sediments Naturally Contaminated With Biogenic Bromophenols, Charles C. Steward, James L. Pinckney, Yvette Piceno, Charles R. Lovell

Faculty Publications

Sediment cores were collected inside and outside of a bed of a bromophenol-producing marine polychaete, Notomastus lobatus, and examined for impact of the bromophenols on sediment microflora and meiofauna around N. lobatus burrows. No significant differences were found between microbial parameters measured inside and outside of the N. lobatus bed. Integrated 6 cm cores taken adjacent to N. lobatus burrows contained 1.2 x 10⁹ bacteria ml^-1. Cell numbers were similar at control sites within the bed, but away from burrows, and not significantly different from cell numbers (1.0 X 10⁹ cells ml^-1) at a …

Sediment-Water Nutrient Flux In Tidal Creeks Of North Inlet, South Carolina, Michael Duane Quillen

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Michael Duane Quillen on December 7, 1992.

Elucidation Of The Complete Azorhizobium Nicotinate Catabolism Pathway, Christopher Kitts, Jerome P. Lapointe, Van Thai Lam, Robert A. Ludwig

Biological Sciences

A complete pathway for Azorhizobium caulinodans nicotinate catabolism has been determined from mutant phenotype analyses, isolation of metabolic intermediates, and structural studies. Nicotinate serves as a respiratory electron donor to O₂ via a membrane-bound hydroxylase and a specific c-type cytochrome oxidase. The resulting oxidized product, 6-hydroxynicotinate, is next reduced to 1,4,5,6-tetrahydro-6-oxonicotinate. Hydrolytic ring breakage follows, with release of pyridine N as ammonium. Decarboxylation then releases the nicotinate C-7 carboxyl group as CO₂, and the remaining C skeleton is then oxidized to yield glutarate. Transthioesterification with succinyl coenzyme A (succinyl-CoA) yields glutaryl-CoA, which is then oxidatively decarboxylated to …

The Expression Pattern Of The Tonoplast Intrinsic Protein Γ-Tip In Arabidopsis Thaliana Is Correlated With Cell Enlargement, Edward Himelblau, Herman Hofte, Dolors Ludevid, Maarten J. Chrispeels

Biological Sciences

The vacuolar membrane (tonoplast) contains an abundant intrinsic protein with six membrane-spanning domains that is encoded by a small gene family. Different isoforms of tonoplast intrinsic protein (TIP) are expressed in different tissues or as a result of specific signals. Using promoter-β-glucuronidase (GUS) fusions and in situ hybridization, we have examined the expression of γ-TIP in Arabidopsis thaliana. GUS staining of plants transformed with promoter-GUS fusions showed that γ-TIP gene expression is high in recently formed tissues of young roots. In the shoot, γ-TIP gene expression was highest in the vascular bundles of stems and petioles, as well as …

Gene Probe Analysis Of Soil Microbial Populations Selected By Amendment With 2,4-Dichlorophenoxyacetic Acid, William Holben, B. M. Schroeter, V. G.M. Calabrese, R. H. Olsen, J. K. Kukor, V. O. Biederbeck, James M. Tiedje

Biological Sciences Faculty Publications

Soils with a history of 2,4-dichlorophenoxyacetic acid (2,4-D) treatment at field application rates and control soils with no prior exposure to 2,4-D were amended with 2,4-D in the laboratory. Before and during these treatments, the populations of 2,4-D-degrading bacteria were monitored by most-probable-number (MPN) enumeration and hybridization analyses, using probes for the tfd genes of plasmid pJP4, which encode enzymes for 2,4-D degradation. Data obtained by these alternate methods were compared. Several months after the most recent field application of 2,4-D (approximately 1 ppm), soils with a 42-year history of 2,4-D treatment did not have significantly higher numbers of 2,4-D-degrading …

Early Behavior Formation In Larval Fathead Minnows, Pimephales Promelas, Shamali Salgado

Masters Theses & Specialist Projects

This study was undertaken in order to identify the approximate times of recruitment of the senses of vision, mechanoreception and chemoreception into the feeding behavior of the fathead minnow, Pimephales promelas, during the first 15 days of life. Larvae were reared on diets of live or freshly killed brine shrimp nauplii and their feeding activity observed daily under light and dark conditions. On every third day during the feeding trials, the larvae were reverse-fed the type of food upon which they were reared. The first evidence of feeding occurred on Day 3, when larvae conditioned on dead food ingested …

Progress In Scanning Electron Microscopy Of Frozen-Hydrated Biological Specimens, René Hermann, Martin Müller

Scanning Microscopy

Modem scanning electron microscopy yields structural information down to 2 to 5 nm from thin, beam transparent biological specimens. This paper examines the possibilities of garnering this level of structural information from bulk, frozen-hydrated samples.

Freeze-fractured, frozen-hydrated yeast cells, frequently taken as a yardstick to monitor progress in low-temperature scanning electron microscopy, have been used to optimize both metal shadowing methods and observation parameters (e.g. accelerating voltage, electron beam irradiation of the specimen).

Uncoated frozen-hydrated yeast cells do not charge electrically at an accelerating voltage of 30 kV. Increasing charging effects are however observed with decreasing accelerating voltages. Very thin …

Scanning Laser Microscopic Surface Profiles Of Human Enamel And Dentin After Brushing With Abrasive Dentifrice In Vitro, Tetsuo Kodaka, Masaru Kuroiwa, Megumi Kobori

Scanning Microscopy

Automatic brushing with and without commercial dentifrice containing calcium hydrogenphosphate as an abrasive, commonly available in Japan, was performed on the tangential ground surfaces of sound enamel and dentin in human young premolar teeth with loading of about 120 g for 10 minutes in vitro. Their brushed surfaces were observed with a scanning electron and a scanning laser microscope. Brushing with abrasive dentifrice caused rough surfaces to appear and the abrasion of the enamel and the dentin was measured to be about 0.1 and 1.5 μm/min in mean depth, respectively. Under brushing with only distilled water, however, the enamel …

Retinol Deficiency And Urinary Stone Disease: Clinical Evidence Is Missing, P. P. Singh, R. Kiran

Scanning Microscopy

Serum retinal levels were studied in : (a) 95, 56 and 43 normal subjects belonging to lower, middle and upper socio-economic groups respectively, (b) 35 adult males suffering from night blindness, (c) 27 subjects with low retinal levels, (d) 8 retinal deficient subjects (e) 17 male infants suffering from overt retinal deficiency, (f) 43 radiologically confirmed stone patients and (g) age and sex matched controls (infants 20; adults 120). The subjects included in groups b to f were clinically and radiologically examined for stone disease. Some inhibitors and promoters of stone disease were estimated in urine in groups b to …

The Tale Of Parathyroid Function In Idiopathic Hypercalciuria, Bernhard Hess, Philippe Jaeger

Scanning Microscopy

At the origin, idiopathic hypercalciuria has been described as a syndrome consisting of normocalcemia, low plasma phosphate levels and abnormally high urinary calcium excretion. The cause of this syndrome was subject to many investigations throughout the years. Two main pathophysiologic hypotheses have been proposed: a) primary intestinal hyperabsorption of calcium, leading to depression of parathyroid hormone (PTH) secretion ("absorptive" hypercalciuria); and b) primary renal tubular leak of calcium which stimulates PTH secretion (secondary hyperparathyroidism). Most of the published studies indicate that intestinal hyperabsorption of calcium with subsequent relative hypoparathyroidism is the primary event causing idiopathic hypercalciuria, and that …

Study Of Surface Modified Poly(Ethylene) Yarns, Samuel H. Cohen, Heidi Schreuder-Gibson, John T. Stapler

Scanning Microscopy

Spectra® fibers and fabrics have been treated to enhance surface friction to determine if ballistic penetration resistance of Spectra fabric can be increased with improved interfiber friction. Scanning electron microscopy (SEM) has shown the extent of surface modification for plasma treated Spectra yarns and the uniformity of coverage for dip-coated yarns and fabrics. Of particular interest is the observation by SEM that plasma gases etch the surface of the polyethylene, producing varying effects on the fiber surface friction. While difficult to measure spectroscopically, the presence of coatings that affect fiber friction are confirmed by SEM.