Digital Commons Network^™

Surface Studies Of Duodenal Lesions Induced By Thoracic Irradiation, K. E. Carr, S. Ellis, A. Michalowski

Scanning Electron Microscopy

Acute duodenal ulcers are produced in mice as a remote ("abscopal") effect of irradiation to the lower mediastinum. Such lesions have been examined with scanning electron microscopy at 5, 8 and 28 days after irradiation with 18 Gy of X-rays. All the ulcers occur within the first 1 cm long segment of the duodenum which is endowed with Brunner's glands. The single lesions vary in size, shape and position. The damaged area often includes much of the duodenal circumference and is distinguished by conical or rudimentary villi, or even by the complete absence of villi. In contrast, around the periphery …

Pollen Wall Structure, A New Interpretation, D. Claugher

Scanning Electron Microscopy

A new preparative procedure using potassium permanganate has enabled previously undescribed structures on the surface and in the walls of pollen grains to be visualised. The results in some respects lend support to predictions that have been made on the ultrastructure of walls which have not been imaged clearly by any presently available technique. The findings may necessitate a reappraisal of current concepts regarding pollen wall structure.

Cell Ultrastructure In Disease, R. Laschi, E. Govoni

Scanning Electron Microscopy

The doctor of today must adopt the 'cellular way of thinking' in the evaluation of diseases. This ultrastructural outlook provides him with much indispensable information that also serves a practical purpose. A diseased cell organelle is at the basis of every clinical sign and any attempt of therapy must be aimed at that specific point of lesion. We intend, in the light of a long experience, to propose to clinicians a new way of thinking in which a precise correlation between symptoms and sub-microscopic changes of the cell is considered. Many different examples amply justify this proposal. Electron microscopy can …

Exocytosis From Large Dense Cored Vesicles As A Mechanism For Neuropeptide Release In The Peripheral And Central Nervous System, Asa Thureson-Klein, Richard L. Klein, Pei-Chun Zhu

Scanning Electron Microscopy

Nerve terminals often contain morphological-distinct populations of large (75-110 nm) and small (45-55 nm) vesicles. The small vesicles are speculated to account for release of transmitter quanta as they accumulate at presynaptic membranes. Large vesicles can co-store neuropeptides and classical transmitters but their function in neurotransmission has been disputed because they do not appear to accumulate at chemical synapses. However, there is now evidence that the large vesicles play a role in neuro-transmission or its modulation even though they may not be eminently involved in synaptic release. Thus, exocytosis occurs along the synapse-lacking membranes of peripheral noradrenergic varicosities. Large vesicles …

Signal Generation And Contrast Mechanisms In Scanning Electron Acoustic Microscopy, N. Kultscher, L. J. Balk

Scanning Electron Microscopy

In scanning electron acoustic microscopy (SEAM) until now the signal generation is explained mainly by an intermediate production of thermal waves. Though this so-called thermal wave approach has proven to give realistic results for metals, from experimental evidence it seems to fail for other material groups such as ceramics, dielectrics, piezoelectrics and semiconductors. As these material groups are of major technological importance, it is necessary to develop theories which help interpreting those SEAM micrographs obtained for these types of material.

In a comparative manner three different models are discussed in this paper, the well known thermal coupling, the piezoelectric coupling …

Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters

Faculty Publications

A method is presented that allows rapid and accurate measurement of changes in the spatial pattern of space occupation in encrusting organisms. The boundaries of organisms are represented as polygons, and geometric difference calculations are used to establish the perimeters of the areas gained or vacated between sampling dates. The influence of interspecific interactions on occupation of space is also quantified: geometric intersection calculations are used to define the perimeters of the areas gained or lost in overgrowth interactions. A method is presented for estimating the sampling frequency necessary for detection of significant changes in occupation of space. The method …

Elemental Content Of Anagen Hairs In A Normal Caucasian Population Studies With Proton Induced X-Ray Emission (Pixe), B. Forslind, H. K. Li, K. G. Malmqvist, D. Wiegleb

Scanning Electron Microscopy

The elemental content of anagen hair fibers in a Caucasian population of healthy females and males in the age range 10-69 years was performed to constitute a baseline for further studies of pathological conditions. Proton induced X-ray emission (PIXE) analyses were performed on single hair fibers in triplicates from 103 individuals in order to determine sulfur, zinc, calcium, and chlorine content. The hair fibers were all anagen hairs collected from a site little influenced by genetic and hormonal influences 1.5 cm above the right ear of the probands.

An area 5-8 mm from the follicle bottom was chosen for minimize …

Lipofuscin Accumulation In Cultured Non-Dividing Cells As A Function Of Time And Oxygen Tension, Anders Brunmark, V. Peter Collins, Howard Thaw, Ulf Brunk

Scanning Electron Microscopy

Cultivated human glial cells, kept in a state of density-dependent inhibition of growth, accumulate age-pigment (lipofucsin) within their lysosomal vacuomes with the same characteristics as the corresponding pigment observed in vivo. The rate of formation and accumulation of lipofuscin is greatly accelerated under the conditions of routine cell cultivation in comparison to the in vivo event. Lipofuscin is generally considered to be composed of polymerized products of lipid peroxidation and thus it would be reasonable to suggest that factors which influence lipid peroxidation would also alter the rate of lipofuscin formation. Human glial cells were grown in the presence …

Calcium And Cystic Fibrosis, Godfried M. Roomans

Scanning Electron Microscopy

Cystic fibrosis (CF) is a generally lethal, congenital, genetic disease of unknown etiology. It is likely that a defective regulation of ion and water transport in exocrine glands and possibly also in other epithelial cells has a central role in the pathogenesis of this disease. Calcium has been implicated in the basic defect underlying CF because of findings of abnormally high calcium levels in some secreted fluids and some cells of CF patients.

Using X-ray microanalysis, we have demonstrated elevated calcium concentrations in cultured fibroblasts and in goblet cells of the bronchial epithelium of CF patients. A factor produced by …

Data Acquisition And Processing Techniques For Voltage Contrast Measurements, F. A. Dibianca, D. G. Johnson, C. R. Bagnell, E. I. Cole, W. V. Oxford, R. H. Propst, C. A. Smith

Scanning Electron Microscopy

The effects of several data acquisition techniques on the accuracy of voltage contrast measurements are studied. In particular, the effect of using a voltage reference region directly connected to an external voltage source in performing the image intensity-to-voltage mapping of a node whose voltage is to be determined is examined. This is found to allow improved voltage measurement. The actual reference curves were obtained by least squares fitting the measured intensity-voltage reference data alternately to a quadratic and a cubic function. In addition, various mapping algorithms are considered including ones based alternately on the use of unprocessed, subtracted and normalized …

Quantitative Renal Vascular Casting In Nephrology Research, Vincent H. Gattone Ii, Andrew P. Evan

Scanning Electron Microscopy

The present paper describes the use of a quantitative renal vascular casting method to study the changes associated with kidney disease. Several animal models of hypertension (spontaneously hypertensive rat, SHR, with its normotensive rat the Wistar Kyoto, WKY; Dahl salt sensitive DS - hypertensive, and salt resistant DR -normotensive) were examined at time points when the systemic blood pressure was rising (6 and 12 weeks of age) and following renal denervation (in SHR-WKY rats). The SHR appears to have a smaller caliber afferent arteriole at both 6 and 12 weeks of age. This difference is probably not entirely due to …

Book Review Of Sociobiology And The Law: The Biology Of Altruism In The Courtroom Of The Future, Gregory S. Alexander

Journal of Legal Education

No abstract provided.

A Review Of Modern Characterization Methods For Semiconductor Materials, T. J. Shaffner

Scanning Electron Microscopy

The manufacture of solid state devices in the microelectronics industry involves crystal growth, slice preparation, diffusion and implantation, oxide and metal deposition, patterning and etching, probe testing and packaging of completed devices. This simplified process flow is adopted in an overview to briefly outline some established as well as newly developed techniques of materials characterization. The complexity of semiconductor processing has imposed greater stringency criteria which have resulted in the revitalization of old methods as well as the development of new techniques capable of extreme sensitivity and spatial resolution.

Examples given for trace impurity and dopant detection include neutron activation …

Conserved Chromosomal Positions Of Dual Domains Of The Ets Protooncogene In Cats, Mice, And Humans, Dennis K. Watson, Mary J. Mcwilliams-Smith, Christine Kozak, Roger Reeves, John Gearheart, Michael F. Nunn, William Nash, John R. Fowle Iii, Peter Duesberg, Takis S. Papas, Stephen J. O'Brien

Biology Faculty Articles

The mammalian protooncogene homologue of the avian v-ets sequence from the E26 retrovirus consists of two sequentially distinct domains located on different chromosomes. Using somatic cell hybrid panels, we have mapped the mammalian homologue of the 5' v-ets-domain to chromosome 11 (ETS1) in man, to chromosome 9 (Ets-1) in mouse, and to chromosome D1 (ETS1) in the domestic cat. The mammalian homologue of the 3' v-ets domain was similarly mapped to human chromosome 21 (ETS2), to mouse chromosome 16 (Ets-2), and to feline chromosome C2 (ETS2). …

The Effect Of Salinity On Habitat Selection Of Two Oregon Chiton Species (Katharina Tunicata And Mopalia Hindsii), David Carl Rostal

Dissertations and Theses

Adult specimens of Katharina tunicata (mean weight = 10.23 grams) and Mopalia hindsii (mean weight = 10.90 grams) were tested for osmotic stress tolerance and oxygen consumption rates in a series of salinities (120%, 100%, 80%, 60%, and 40% seawater) at 11°C and 16L:8D photoperiod. K. tunicata and M. hindsii displayed similar trends in percent body weight variation and volume regulatory responses to osmotic stress. However, K. tunicata experienced a significantly higher percent body weight increase than did M. hindsii in response to hypo-osmotic conditions (80%, 60%, and 40% seawater). The mean rates of oxygen consumption per salinity for the …

Plant Ultrastructure In The Scanning Electron Microscope, Susan H. Barnes, Stephen Blackmore

Scanning Electron Microscopy

Preparative techniques which have been used to study internal details of plant cells in the scanning electron microscope are reviewed. A number of methods have previously been described which involve selective extraction of materials from freeze-fractured surfaces and can be referred to as freeze-fracture and cytoplasmic maceration. One of these techniques which involves an extended period of cytoplasmic maceration with dilute osmium tetroxide has been applied to the study of Cichorium intybus (chicory) pollen ontogeny. The results obtained, including changes in the numbers of mitochondria and the form of endoplasmic reticulum during the course of development demonstrate the value of …

Prezygotic Male Reproductive Effort In Insects: Why Do Males Provide More Than Sperm, James S. Quinn, Scott K. Sakaluk

Faculty Publications – Biological Sciences

Males' incentives for providing benefits to females and/or their offspring are ambiguous during the period prior to zygote formation. The benefits may function to increase the number of available eggs fertilized by a male and/or enhance the production and survival of his offspring. In some cases, male prezygotic investment may be an adaptation to secure fertilizations despite the fact that it incidentally benefits the female or her offspring. More often, the benefits to offspring production and survival are not simply incidental and probably account, in part, for the magnitude of the male investment. Regardless of the adaptive significance of male …

Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue

Dartmouth Scholarship

Microtubule proteins isolated from calf brain will undergo gelation-contraction in the presence of ATP. We have now examined this process by video-enhanced contrast microscopy. After ATP addition to steady-state microtubules, slow (1-5 micron/min), linear movements of particles and microtubules toward aggregation centers occur. The resulting structures resemble mitotic spindle asters. During the time when gel contraction occurs, asters move (at 1-5 micron/min) toward other nearby asters. This is accompanied by the apparent shortening of the microtubules running between the asters. This is the first example of isolated microtubules undergoing a process that has similarities to half-spindle shortening during anaphase A. …

Multiple Mating, Sperm Competition And The Fertility Component Of Fitness In Drosophila-Pseudoobscura, Monte E. Turner

Biology Faculty Research

Those aspects of an organism's biology that influence the number of progeny produced make up the fertility component of its fitness. The fertility of both male and female Drosophila pseudoobscura is influenced by multiple matings. In the former, rates of multiple matings and the genotypes of females' other mates interact to affect male fitness. Female fecundity and productivity increases with multiple matings, while longevity declines. Mating rates could be the result of these conflicting selection pressures. Density is a non-genetic factor influencing multiple mating. The mechanisms by which multiple matings increase female fertility is not the same in different species …

Surface Morphology Of Unused And Used Hydromerr-Coated Intravenous Catheters, A. Bylock, E. Hultman, B. Gustavsson, L. E. Linder, I. Curelaru

Scanning Electron Microscopy

Hydromer^R-coated polyurethane (Erythroflex)^R catheters, unused, or intravenously inserted for 2-20 days, were studied by scanning electron microscopy (SEM). Both unfixed and fixed (2% glutar-aldehyde in phosphate buffer), and air-or critical-point dried (CPD) specimens were investigated. The catheter segments were sputter-coated with approx. 20 nm gold and studied at an accelerating voltage of 20 kV. The specimens were examined for surface depositions, thickness and structure of the Hydromer^R layers, and occurrence of adhering and embedded bacteria.

The outer Hydromer^R layer showed, in the un-used specimens, scratches and fissures, as well as adhering foreign bodies. In used …

Concerning The Problem Of High Depth Resolution Using Ion Sputtering, G. Blaise

Scanning Electron Microscopy

The inhomogeneity of ion bombardment, the angular dependence of sputtering yields and the crystalline orientation of samples are the three main causes of the degradation of resolution with depth. It is possible to reduce these effects by bombarding at low energy (≈ 1 keV). A low-energy ion-bombardment device is described which has been adapted for use on our sputtered thermal-ion source mass spectrometer.

The Quick-Freezing Of Single Intact Skeletal Muscle Fibers At Known Time Intervals Following Electrical Stimulation, Rashid Nassar, Nancy R. Wallace, Isaiah Taylor, Joachim R. Sommer

Scanning Electron Microscopy

Single intact frog skeletal muscle fibers quick-frozen after known time intervals following electrical stimulation are examined electron microscopically in thin sections, after freeze-substitution, in freeze-fracture/etch preparations, and in cryosections prepared for x-ray microprobe analysis. Techniques are described to perform these operations on a single fiber. Notable morphological differences between conventionally fixed and cryopreserved muscle fibers, and between fibers quick- frozen at different post-stimulation intervals are demonstrated.

Scanning Electron Microscopy Of Human Metaphase Chromosomes, T. D. Allen, E. M. Jack, C. J. Harrison, D. Claugher

Scanning Electron Microscopy

Preparative methods for scanning electron microscopy of chromosomes are dependent on the original source of material. Chromosomes extracted from unfixed metaphase cells via isolation buffers tend to show topography and surface morphology which may have been induced by the choice of isolation buffer itself. Furthermore, this type of preparation often precludes any chromosome identification, as many metaphases have been pooled, and also the chromosomes from these preparations are not suitable for the banding techniques regularly used in clinical cytogenetics. Our own approach has been to use the standard cytogenetic approach, starting with methanol-acetic acid fixed, air dried metaphase spreads, allowing …

Deconvolution In Auger Electron Spectroscopy, B. Chornik, H. E. Bishop, A. Le Moel, C. Le Gressus

Scanning Electron Microscopy

Deconvolution calculations have been applied in Auger Electron Spectroscopy to increase resolution and/or to eliminate loss features. We present: i) A short review of the methodology; ii) Recent results obtained in our laboratory in spectroscopy of Al, Ni, Cu, Ag and Te; iii) A discussion on the conditions for the appearance of artefacts originating either in the calculation or the physical processes (emission anisotropy, distribution of electron path lengths, and intrinsic losses).

Cloning And Comparison Of Repeated Dna Sequences From The Human Filarial Parasite Brugia Malayi And The Animal Parasite Brugia Pahangi, Larry A. Mcreynolds, Susan M. Desimone, Steven A. Williams

Biological Sciences: Faculty Publications

No abstract provided.

Analytical Ultra High Vacuum Scanning Electron Microscopy With Field Emission Gun For Surface Study, P. Morin, P. Abraham, C. Bablet, M. Tholomier

Scanning Electron Microscopy

Surface studies can be carried out with a scanning electron microscope (SEM) having an ultra high vacuum specimen chamber. The main application of this SEM was the micro Auger analysis, but it is also interesting to combine the usual surface study technique with SEM observations. Indeed, these latter give valuable in formation about the topographic, chemical and crystallographic aspects of the surface when the secondary, backscattered and transmission SEM modes are used. The SEM performances are increased by the use of a field emission gun, the high brightness beam of this gun gives new observation possibilities such as the imaging …

Genetic Engineering, W. John Hayden

Biology Faculty Publications

Why do so many biologists express so little concern for biology as a whole and such contempt for fields other than their own? The current debate on release of genetically engineered organisms into the environment, specifically, J. E. Fox's recent reply (Letters, 18 Oct., p. 237) to an earlier letter by R. K. Colwell et al. (12 July, p. 111), offers a case in point.

A Dna Sequence Analysis Program For The Apple Macintosh, Robert H. Gross

Dartmouth Scholarship

This paper describes a new set of programs ^* for analyzing DNA sequences using the Apple Macintosh computer, a computer ideally suited for this kind of analysis. Because of the Macintosh interface and the availability of high quality software-only speech synthesis, these programs are truly easy to use. Instead of typing in commands, the user directs the program by making selections with the mouse, thereby eliminating most typographical and syntax errors. Output options are selected by “pressing buttons” and then clicking “OK” with the mouse. DNA sequences are confirmed by having the program speak them. The high resolution graphics on …

Cytoskeletal Changes During Adhesion And Release: A Comparison Of Human And Nonhuman Primate Platelets, J. C. Lewis, M. S. White, T. Prater, K. R. Porter, R. J. Steele

Scanning Electron Microscopy

The organization of cytoskeletal proteins in whole-mount adherent platelets from African green monkeys and normal human volunteers has been studied by SEM, high vacuum electron microscopy (HVEM) and conventional (120 kV) electron microscopy. We describe three distinct organizational zones, the Central Matrix, the Trabecular Zone and the Peripheral Web in spread platelets from both sources. The Central Matrix is an ill-defined superstructure of 80-100 Å filaments of short length which enshrouded the granules, dense bodies, mitochondria and elements of the open-channel and dense-tubular systems. The latter, identified through the use of peroxidase cytochemistry with the whole mounts, is an anastomosing …

Limnological Aspects Of Upland Island: A Wilderness Area In East Texas, J. A. Sidnell, C W. Reed, J. D. Mccullough

Faculty Publications

No abstract provided.