Life Sciences Commons^™

Early Phase Changes During The Setting Of High Copper Amalgams, T. Ruzickova, J. Had

Scanning Microscopy

X-ray diffraction analysis has been used to evaluate the phase composition of two (spherical and lathe cut) HCSC amalgam alloys and early phase changes in these amalgam in the time interval 2.5 min to 7 days after trituration. A method appropriate for the evaluation of these changes was developed. Only two phases were found in alloys Valiant and Ana 2000: gamma(Ag₃Sn) and epsilon(Cu₃Sn). In amalgams, no diffraction peaks were observed corresponding to gamma 2 phase in the time interval form 2.5 min to 7 days after trituration. The relative concentration changes of the reaction products of …

A Simulation Of Secondary Electron Trajectories In Solids, M. Kotera, T. Kishida, H. Suga

Scanning Microscopy

A Monte Carlo calculation model is introduced to simulate not only the primary electron behavior but also the secondary electron cascade in a specimen bombarded with an electron beam. Electrons having energy greater than 0.1keV are treated as "fast electrons" and the single scattering Monte Carlo model is adopted. Electrons having energy smaller than 0.1keV are treated as "slow electrons" and the electron cascade Monte Carlo model is used. The calculated results for the energy distribution of secondary electrons, and primary electron energy dependence of the total secondary yield and the backscattering yield are in good agreement with experimental results.

Strontium And Bromide As Tracers In X-Ray Microanalysis Of Biological Tissue, Joanna Wroblewski, Samuel Sagström, Helmy Mulders, Godfried M. Roomans

Scanning Microscopy

Since energy dispersive X-ray microanalysis cannot distinguish between isotopes of the same element, alternative methods have to be used to get information similar to that obtained in experiments with radioactive tracers. In the present study, strontium was used as a tracer for calcium, and bromide as a tracer for chloride. Rats were injected with strontium chloride in vivo, and the uptake of strontium in the acinar cells of the submandibular gland was studied. Eventually a Sr/Ca ratio of 0.3 was reached. In some animals, secretion of mucus had been elicited by stimulation with isoproterenol 4 h prior to injection …

Backscattered Electron Imaging Using Single Crystal Scintillator Detectors, R. Autrata

Scanning Microscopy

The image obtained by the detection of backscattered electrons (BSE) becomes an indispensable complement to the correct interpretation and more precise reconstruction of the surface of the specimen and its material composition. The BSE are carriers of information which is dependent on their angular and energy distribution. The choice of a certain type of BSE and their efficient detection make it possible to record the desired information with a different grade of quality. The knowledge of the angular and energy distribution of BSE is necessary for the adjustment of the correct position of the BSE detector with regard to the …

Bone Lining Cells: Structure And Function, Scott C. Miller, Louis De Saint-Georges, Beth M. Bowman, Webster S. S. Jee

Scanning Microscopy

Bone lining cells (BLC's) cover inactive (nonremodeling) bone surfaces, particularly evident in the adult skeleton. BLC's are thinly extended over bone surfaces, have flat or slightly ovoid nuclei, connect to other BLC's via gap junctions, and send cell processes into surface canaliculi. BLC's can be induced to proliferate and differentiate into osteogenic cells and may represent a source of "determined" osteogenic precursors. BLC's and other cells of the endosteal tissues may be an integral part of the marrow stromal system and have important functions in hematopoiesis, perhaps by controlling the inductive microenvironment. Because activation of bone remodeling occurs on inactive …

Practical Aspects Of Automatic Orientation Analysis Of Micrographs, N. K. Tovey, P. Smart, M. W. Hounslow, X. L. Leng

Scanning Microscopy

Techniques to analyse the orientation of particulate materials as observed in the scanning electron microscope are reviewed in this paper. Emphasis is placed on digital imaging, processing, and analysis methods, but many secondary electron images are not amenable to traditional image processing as adequate thresholding is often difficult to achieve. Evaluation of the intensity gradient at each pixel offers an alternative approach, and this method is described in detail including the latest developments to generalize the technique. Practical points in the acquisition, processing and analysis of the images are considered and several images, including both synthetically generated and actual back-scattered …

Osteoclast Features Of Cells That Resorb Demineralized And Mineral-Containing Bone Implants In Rats, Cedo M. Bagi, Scott C. Miller

Scanning Microscopy

The comparative temporal tissue response to demineralized bone matrix powder (DBP) and devitalized mineral containing bone powder (MCP) implanted subcutaneously in rats was studied. The tissue response to implanted DBP followed the well described endochondral osteogenic pathway and included the appearance of osteoblasts and osteoclasts. On the other hand, implanted MCP resulted in the appearance of a large population of giant cells that resorbed the implants. At later times (3-4 weeks), most of the cells in the MCP implants appeared as typical foreign body giant cells with extensive membrane foldings, usually away from bone surface. Some cells did, however, have …

Structural And Compositional Changes In Aging Bone: Osteopenia In Lumbar Vertebrae Of Wistar Female Rats, M. Silbermann, M. Safadi, D. Schapira, I. Leichter, R. Steinberg

Scanning Microscopy

Changes in vertebral bone mineral content and density during aging were quantified in female Wistar rats. This study represents a longitudinal follow up utilizing single photon absorptiometry for the measurement of bone mineral content (BMC), quantitative computed tomography (OCT) for the measurement of bone mineral density (BMD), and image analysis histomorphometry for the measurement of trabecular bone volume (TBV) and bone cortical area (BCA). The above measurements were accompanied by biochemical assays of calcium concentrations in the respective bones. All aging animals experienced significant decreases in BMC, BMD, TBV, BCA and in the calcium content of their bones. The above …

Bacillus-Shaped Deposits Composed Of Hexahedrally Based Crystals In Human Dental Calculus, T. Kodaka, A. Hirayama, K. Miake, S. Higashi

Scanning Microscopy

In human supra- and subgingival calculus, bacillus-shaped deposits showing various rocky-pile forms composed of hexahedrally based crystals were observed by scanning electron microscopy. The crystal size measured approximately 0.1 - 1.5 μm. The electron probe microanalysis always detected calcium, phosphorous, and magnesium. Their molar ratios resembled those of magnesium-containing whitlockite and moreover the crystals also gave the electron diffraction pattern of whitlockite. The bacillus-shaped deposits happened to coexist with the intracellular calcifying microorganisms, furthermore, oral microorganisms partially replaced by the hexahedrally based crystals were found. The crystal deposits were never seen in the surface layers of calculus exposed to the …

Microprobe Analysis Of Element Distribution In Bovine Extracellular Matrices And Muscle, M. B. Engel, H. R. Catchpole

Scanning Microscopy

The concentrations of some essential elements, Na, K, P, S and Cl were determined by microprobe analysis in bovine extracellular matrices of cartilage, tendon and elastic tissue (ligamentum nuchae) and in muscle cells. The values for the different tissues were compared and related to the blood electrolyte concentrations. Among the connective tissues the highest Na and lowest Cl values were found for cartilage which bears a high negative charge. The lowest concentrations of these elements occurred in elastic tissue which is relatively non-polar. In the three extracellular matrices sodium levels exceeded potassium. In myofibers potassium was the major cation at …

Data Acquisition And Presentation In Scanning Nuclear Microprobe Analysis, K. G. Malmqvist, N. E. G. Lövestam, J. Pallon, U. A. S. Tapper

Scanning Microscopy

The data acquisition is a very important part of the scanning nuclear microprobe instrument. To make full use of the potential of the technique an adequate system for acquiring, storing, processing and presenting the data is a prerequisite. Various principles applied are presented including the list mode approach, which facilitates flexible off-line data processing. As in the case of the electron probe the beam-induced effects in the sample may be substantial and the list mode acquisition can then also be used to monitor and correct for any such effects. A comprehensive system for scanning nuclear microprobe control and data acquisition, …

Quantitative Measurement From Vascular Casts, Ralph G. Kratky, Christine M. Zeindler, Dorian K. C. Lo, Margot R. Roach

Scanning Microscopy

A review of quantitative measurements show casting materials shrink from 0.2 - 20% and have viscosities ranging from 1.4 - 100,000 centipoise. Blood vessels have highly variable mechanical properties. Some microvessels are very stiff having little change in dimensions with pressure. Larger vessels generally change diameter significantly but show highly variable changes in length with pressure. Perfusion fixation does not fix the dimensions of blood vessels. Dog carotid arteries well fixed with glutaraldehyde at physiologic dimensions retain ≈20% of their elastic recoil circumferentially and ≈30% longitudinally. We recommend vascular casting as a method of accurately measuring the vasculature if care …

Oxalate Crystallization In The Kidney In The Presence Of Hyperuricemia, Shinshi Noda, Kenichi Hayashi, Kousaku Eto

Scanning Microscopy

It has been a long time since uric acid was suggested to be a promoting factor in calcium oxalate stones, and a number of in vitro studies have been carried out on the relationship between uric acid or urate and calcium oxalate.

Concerning in vivo studies, urate or calcium oxalate stone-forming diets were given alone in most cases, and diets that induce formation of stones with different composition have not been given in combinations. We administered a low-concentration oxalemic diet, and a mixed diet containing oxalic acid and uric acid, and biochemically and histologically studied the effects of oxalate and …

Surface Heterogeneity Of Tumor Cells And Changes Upon Ionizing Radiation, Z. Somosy, Orsolya Csuka, Tamara Kubasova, J. Kovács, G. J. Köteles

Scanning Microscopy

Heterogeneous distribution of surface domains is a characteristic feature of the tumor cell surface and the distribution differs from that of normal cells. During the malignant transformation the heterogeneity may change or disappear. Cell lines with various metastasizing capacities show different distributions of membrane domains or other differences in membrane or surface organization. We have demonstrated that the amount and distribution of negatively charged sites of B 16 melanoma membranes changed upon ionizing radiation (X-ray, ⁶⁰Co-gamma). In the case of the P 388 lymphoma, however, only the amount of negatively charged sites change after irradiation, the distribution remains unaltered. …

The Physical State Of Potassium In The Human Lymphocyte: A Review, William Negendank

Scanning Microscopy

Studies of the effects of chemical potential, temperature, and metabolic perturbation on static ion contents, kinetics of the approach to equilibrium, and kinetics of ionic self-exchange in human lymphocytes are reviewed. The results contradict the classical concept of cell ion and water physiology, the membrane-osmotic, pump-leak theory, and are re-interpreted by an adsorption model of the cell. In this model, most of cell water exists in a physical state sufficiently ordered to reduce the partition function of dissolved ions, and most of cell potassium is associated with fixed charges on macromolecules. Competing adsorption of potassium and sodium is cooperative and …

Gastrointestinal Surface Changes: Interpretation Problems And Indexing Possibilities (A Review), C. J. Pfeiffer, O. Bulbena

Scanning Microscopy

The purpose of this review on state-of-the-art and new perspectives on the use of scanning electron microscopy (SEM) in gastrointestinal pathology is to discuss the possibility of developing an index for quantitatively grading mucosal epithelial injury. This topic is reviewed within the framework of ulcer indices previously developed for gross lesions, where analogous problems exist, and in relation to the transmission electron microscope staging of epithelial cell pathology. If such an index could be developed it would increase objectivity and standardization of data analysis from laboratory to laboratory, and would allow for quantitative and statistical analysis of morphometric data. It …

Scanning Tunneling Microscopy And Fabrication Of Nanometer Scale Structures At The Liquid-Gold Interface, J. Schneir, H. H. Harary, J. A. Dagata, P. K. Hansma, R. Sonnenfeld

Scanning Microscopy

The Scanning Tunneling Microscope (STM) can image gold surfaces covered with a variety of liquids. This paper reviews the results obtained using the STM to image gold surfaces covered with liquid. These results include the creation of 10 nm structures, images of the electrochemical process of electroplating, and the production of atomically flat Au (111) surfaces. We conclude that in the future STM will find further application in the area of nanostructure fabrication and electrochemistry. The trend in the field is toward greater control of the electrochemical environment.

Morphology And Chemical Composition Of Dental Calculi Mainly Composed Of Whitlockite, Toshiro Sakae, Hirotsugu Yamamoto, Hiroyuki Mishima, Takashi Matsumoto, Yukishige Kozawa

Scanning Microscopy

The morphology and chemical composition of two subgingival calculus samples, which were composed of magnesium-whitlockite with a Mg/Ca molar ratio of approximately 0.1 as shown by X-ray powder diffraction, were analyzed semiquantitatively using energy-dispersive spectroscopy (EDS) combined with scanning electron microscopy (SEM). The Ca/P molar ratio values for 33 EDS-analyzed materials ranged from 1.24 to 2.03 with an average of 1.49, and the (Mg+Ca)/P molar ratio values ranged from 1.43 to 2.28 with an average of 1.63. The average Mg/Ca molar ratio was 0.10, a value very close to that obtained by X-ray diffraction analysis.

The EDS-analyzed materials were grouped …

Glover's Silkmoth, Hyalophora Gloveri (Strecker) (Lepidoptera: Saturniidae), New To British Columbia, R. A. Cannings, C. S. Guppy

Aspen Bibliography

Two rather common species of giant silkrnoths of the subfamily Satumiinae (Lepidoptera: Satumiidae) occur in southern British Columbia. Both species, the Polyphemus Moth (Antheraea polyphemus [Cramer]) and the Ceanothus Silkrnoth (Hyalophora euryalis [Bois-duvall) are large and spectacular, and evoke comment from anyone who sees them. Both range northwards to at least the central Cariboo region. Three other striking species of the subfamily occur in the Peace River district of Alberta, but these moths, the Cecropia Moth (Hyalophora cecropia [Linnaeus]), the Columbia Silkmoth (H. columbia [S.L Smith]), and Glover's Silkrnoth (H. gloveri [Strecker l) have never …

Cation Nuclear Magnetic Resonance (Nmr). 7li- And 23na-Nmr Results Obtained With Human Erythrocytes, Jan F. M. Post

Scanning Microscopy

A short discussion of practical results and theoretical aspects of nuclear magnetic resonance (NMR) on intracellular monovalent cations is presented. ⁷Li- and ²³Na-NMR relaxation studies on human erythrocytes are described which indicate that lithium and sodium ions are essentially free inside the cell. However, there is a contribution to transverse relaxation originating from cations diffusing through electric field gradients imposed by the cytoskeleton, which is reflected in the NMR line shape. ³⁹K-NMR results obtained by other authors for intracellular potassium are compared with the ⁷Li- and ²³Na-NMR results presented here. The few ³⁹K-NMR results …

Simultaneous Micro-Characterization Of The Superconducting And Structural Properties Of High-Tc Superconducting Films, R. P. Huebener, R. Gross

Scanning Microscopy

Important information on the local values of the critical temperature and the critical current density in high-T_c superconducting films is obtained by low-temperature scanning electron microscopy (LTSEM). The imaging principle of LTSEM is based on the local beam-induced heating effect and the detection of a voltage response signal in the current-biased specimen film. During the scanning process the sample is mounted on a low-temperature stage the temperature of which is electronically stabilized at some specific value in the range of interest. The local superconducting quantities measured by LTSEM can be correlated with the microstructure of the specimen film investigated …

Effects Of Free-Ranging Cats On Wildlife: A Progress Report, J. S. Coleman, S. A. Temple

Wildlife Damage Management Conference

We have embarked upon a three-year study to determine the density and distribution of free-ranging cats (Felis catus) and their effects on prey populations in rural Wisconsin. The effects of predation by free-ranging cats on wildlife populations are potentially great and have not been adequately accounted for in wildlife management programs. In rural Illinois there was an average of 5.6 free ranging cats per farm (Warner 1985). If densities elsewhere are similar, then a state such as Wisconsin, with over 200,000 active and retired farms, could have over 1 million free-ranging cats on farms. In other studies (Bradt …

Survey Of Mississippi Catfish Farmers On Means, Effort, And Costs To Repel Fish-Eating Birds From Ponds, A. R. Stickley, K. J. Andrews

Wildlife Damage Management Conference

Eighty-seven percent of 281 Mississippi catfish farmers felt that fish-eating birds were enough of a problem to warrant harassment. Farmers estimated that they spent an average of 2.6 man-hours per day harassing birds at an average annual cost of $7400. Sixty percent of the farmers who harassed birds did so by driving around the ponds and firing at birds to repel them. Propane exploders and pyrotechnics were also used. Pyrotechnics were judged the most effective repellent technique. The cost of bird harassment according to these farmers is $2.1 million. The value of fish loss to cormorants alone is roughly estimated …

An Automatic Trigger For Bird Frightening Devices, Steve Price, John Adams

Wildlife Damage Management Conference

This triggering unit for animal frightening devices was developed because of an expressed need for a more effective method of breaking up starling and grackle roosts. The USDA, Animal Damage Control (ADC) office in Louisville, KY suggested that a device which detected the presence of the birds before activating and then emitted different sounds would be much more effective than single functioning devices on timers. Existing frightening devices have limited effectiveness because the birds become accustom to the repeated and periodic actuations of the same thing over and over again. In November of 1986, Mr. Bernice Constantin, District Supervisor for …

The Effectiveness Of Orco Mole Bait In Controlling Mole Damage, Dale K. Elshoff, Glenn R. Dudderar

Wildlife Damage Management Conference

The tunneling damage caused by eastern moles (Scalopus aguaticus) and starnosed moles (Condylura cristata) is well known to professionals in lawn care, golfcourse maintenance, and turfgrass production, as well as many private landowners. Present damage control methods, including trapping, gas and smoke fumigants, and insecticide applications have a wide variety of limitations and prove impractical in some situations. An easily applied mole damage control method is needed that professional and nonprofessional applicators can use in a variety of environmental and physical conditions.

This study tested the effectiveness of Orco Mole Bait, a chlorophacinone pellet placed in …

Depredation Permits For Migratory Birds, Larry L. Hood

Wildlife Damage Management Conference

All of the native species of birds in the United States are protected by either federal or state laws. Under the Migratory Bird Treaty Act, the federal government has formulated regulations that assist in controlling protected species that cause economic damage or health hazards. These regulations are in Subpoint D of Part 21, Title SO Code of Federal Regulations, and may take the form of standing depredation orders or permits issued to kill those species that cause problems.

An Investigation Of Animal Damage Associated With Maple Syrup Production, J. Alan May, Dennis Slate

Wildlife Damage Management Conference

An increase in the use of plastic tubing systems to collect sap from sugar maples (Acer saccharum) has allowed syrup producers to boost production in recent years, but not without cost. Rodents gnawing on tubing, spouts, and fittings may cause damage in excess of $300,000 annually in Vermont, the largest maple producing state. Red squirrels (Tamiasciurus hudsonicus), gray squirrels (Sciurus carolinensis), and chipmunks (Tamias striatus) appear to be responsible for the majority of damage. Other species including flying squirrels (Glaucomvs sabrinus), white-footed mice (Peromvscus leucopus), porcupines (Erethizon …

Revolution In Bird Control, Air Birdstrike Prevention Inc.

Wildlife Damage Management Conference

Over 90% of all civil bird strikes in the U.S. occur at altitudes up to 3,000 feet above the ground and in the close vicinity of the airport. Many species of birds are involved, but almost 50% of all strikes involve gulls.

A Review Of The Status Of Bird Management Products And Devices In The United States, Charles W. Areson

Wildlife Damage Management Conference

Commercial urban /industrial structural pest bird control is approaching a time of crisis. Several long-standing toxicants that have been used as a major part of pest bird control programs are either suspended, at risk of suspension, or have had their production terminated by the manufacturer. "Environmental groups" are up in arms about the use and misuse of pesticides. Lawsuits have been filed to stop the use of some products, and political pressure has brought about reviews of some pesticide products on both the state and federal levels. EPA has seemed to have a "get tough" policy in its reregistration guidelines, …

Laughing Gulls At Jfk Airport: Safety Hazard Or Wildlife Resource?, R. A. Dolbeer, M. Chevalier, P. P. Woronecki, E. B. Butler

Wildlife Damage Management Conference

John F. Kennedy International Airport is adjacent to Jamaica Bay Wildlife Refuge administered by the National Park Service. In 1979, 15 pairs of laughing gulls (Larus atricilla) nested on the refuge, the first recolonization of Long Island by this species since the gulls' disappearance from New York around 1900. The colony, with nests as close as 0.4 km to 1 runway, has subsequently increased to about 3,000 pairs. From 1970 to 1978, only 1 laughing gull strike by an aircraft was recorded at JFK. From 1979 through August 1989, 800 strikes were recorded, including 179 in 1989, in spite of …