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Cell Adhesion To Crystal Surfaces: A Model For Initial Stages In The Attachment Of Cells To Solid Substrates, D. Hanein, B. Geiger, L. Addadi

Cells and Materials

This study addresses the mechanism of the chirally-restricted, ROD-independent adhesion of A6 epithelial cells to the {011} faces of calcium {R,R)-tartrate tetrahydrate crystals. The extensive and rapid adhesion of the cells to these surfaces, in the presence or absence of serum proteins, is distinctly different from the extracellular matrix-mediated adhesion to conventional tissue culture surfaces or to the {101} faces of the same crystals. The differences are manifested by insensitivity to ATP depletion, to disruption of microfilaments and microtubules and even to formaldehyde fixation of the cells. Furthermore, trypsin pretreatment does not affect cell attachment to the {011} faces, nor …

Optical Studies Of Ingaas/Gaas Multiple Quantum Wells (Mqw's) And Gaas/Si Using Novel Scanning Electron Microscopy Based Techniques, D. H. Rich, H. T. Lin, Y. Tang, K. Rammohan, A. Larsson

Scanning Microscopy

The influence of defects on electron-hole plasma transport in nipi-doped in _0.2Ga_0.8As/GaAs multiple quantum wells (MQWs) has been studied using a novel technique called electron beam induced absorption modulation (EBIA) imaging. Modulation doped MQW structures exhibit large optical nonlinearities and are important for the development of all-optical spatial light modulators used in optical computing and communication. The electron-hole plasma is generated by a high-energy electron beam in a scanning electron microscope and is used as a probe to study the MQW absorption modulation induced locally by the electron beam. The influence of structural defects on the …

Time-Resolved Luminescence From Two-Dimensional Electrons In High Magnetic Fields: A Tool For Studying The Fractional Quantum Hall Effect, Rolf J. Haug, Igor V. Kukushkin

Scanning Microscopy

Time-resolved magnetoluminescence investigations of specially doped AlGaAs/GaAs heterostructures allow the study of the electronic properties of two-dimensional electrons. The interactions of the two-dimensional electrons lead in high magnetic fields to the fractional quantum Hall effect. By analyzing the mean energy of the recombination line observed in the luminescence spectrum, the electronic properties of the fractional quantized states can be deduced. For negligible interaction between the charged acceptors and the interacting electron system, the derivative of the mean energy versus filling factor allows to obtain the jump of the chemical potential in crossing a fractional filling factor. From these jumps, the …

Reliability Of Human Fresh And Frozen Gingiva Explant Culture In Assessing Dental Materials Cytocompatibility, R. Warocquier-Clerout, G. C. Hachom-Nitcheu, M. F. Sigot-Luizard

Cells and Materials

An explant culture of human gingival epithelium has been set up in order to provide a valuable test for evaluating the cytocompatibility of dental material s. In an attempt to supply a bank of gingiva ex plants, frozen and freshly excised specimens were cultured in parallel. Optical and scanning electron microscopy showed an early release of cuboidal cells forming a dense layer around the explants. Afterwards, cultures evolved differently . Spread cells grew and migrated more rap idly in fresh than in frozen explant cultures but their adhesion to substratum increased earlier in frozen ones. Epithelial phenotype of cells had …

Biomaterials Associated Infections: The Scale Of The Problem, David J. Stickler, Robert J. C. Mclean

Cells and Materials

The biomaterials used in the manufacture of implanted prosthetic devices profoundly impair the host's ability to opsonise and phagocytose invading microbes. As a result, while these devices generally provide effective relief from painful, crippling and life-threatening disorders, they can also induce vulnerability to infection in the recipients. The surfaces of the implants are susceptible to colonisation by microbial biofilms. The cells in the biofilm.s are further protected against opsonophagocytosis and are also resistant to antibacterials. Device associated infections thus tend to be refractile to antibiotic therapy and in many cases the device has to be removed before the infection will …

Feasability Of Preventing Encrustation Of Urinary Catheters, J. M. Bibby, A. J. Cox, D. W. L. Hukins

Cells and Materials

Colonization of urinary catheters by bacteria which produce urease leads to an increase in urine pH, followed by deposition of the minerals struvite and hydroxyapatite. Adhesion of these encrusting deposits can be reduced, but not prevented, by using catheters with a smooth surface finish. Chemical methods for preventing encrustation are not completely satisfactory. A better way of preventing encrustation would be to prevent colonization of the catheter by bacteria. This might be achieved by controlled release of antimicrobial agents directly into the urine from the catheter itself. Preliminary experiments have demonstrated the feasibility of controlled release from solid silicone. However, …

Biphasic Sodium Fluoride Effects On Bone And Bone Mineral: A Review, P. -T. Cheng, S. M. Bader, M. D. Grynpas

Cells and Materials

This paper reviews the clinical and experimental findings on the effects of sodium fluoride (NaF) on human and animal bone. NaF has been shown to cause a significant increase in axial skeletal bone mass. However, there is concern that the new bone may not provide the desired increase in bone strength. Yet, NaF remains the most commonly used agent capable of stimulating bone formation in most patients (30% non-responders). But whether NaF reduces vertebral fracture rate (VFR) remains controversial. For a given treatment duration, the effect of F on bone quality appears to depend on dose: there is a marked …

Luminescence From Semiconductor Quantum Wires, Quantum Dots, And Monolayer Quantum Wells: Bottleneck And Localization Issues, C. M. Sotomayor Torres, P. D. Wang, N. N. Ledentsov, Y. -S. Tang, H. Qiang, F. H. Pollak, H. F. Ghaemi, B. B. Goldberg

Scanning Microscopy

Semiconductors nanostructures are fabricated using a range of techniques which inevitably have an impact in the resulting optical properties. Multilayers are grown by epitaxial techniques with a varying degree of uniformity in thickness, composition, etc., all leading to localisation effects in two-dimension. These multilayers are patterned to fabricate wires and dots using, in this case, electron beam lithography and dry etching. The fabrication steps contribute to modifications of the optical properties, beyond the expected purely confinement-related effects.

An overview of linear and modulation spectroscopy is presented to demonstrate the impact of fabrication steps as well as of lateral confinement upon …

Natural History Of Bone Response To Hydroxyapatite-Coated Hip Prostheses Implanted In Humans, P. Frayssinet, D. Hardy, J. S. Hanker, B. L. Giammara

Cells and Materials

A series of 15 autopsied femurs containing hydroxyapatite- coated (HA-coated) prostheses was analysed histologically. Their implantation time ranged from 5 days up to 3 years. The coating thickness of some prostheses and the percentage of the coating in contact with bone at different levels were evaluated using an image analysis device. After the newly formed bone tissue had became mature, several bone morphotypes were identified at the coating contact. From the proximal to the distal part of the prosthesis, bone morphotype was denser and the percentage of the coating surface in contact with bone increased. Several stages in the prosthesis …

Department Of Energy Programmatic Spent Nuclear Fuel Management And Idaho National Engineering Laboratory Environmental Restoration And Waste Management Programs Final Environmental Impact Statement, Volume 1, Appendix A, United States Department Of Energy

All U.S. Government Documents (Utah Regional Depository)

The U.S. Department of Energy (DOE) is currently deciding the direction of its environmental restoration and waste management programs at the Idaho National Engineering Laboratory (INEL) for the next 10 years. Pertinent to this decision is establishing policies for the environmentally sensitive and safe transport, storage, and management of spent nuclear fuels (SNF). To develop these policies, it is necessary to revisit or examine the available options. As a part of the DOE complex, the Hanford Site not only has a large portion of the nationwide DOE-owned inventory of SNF, but also is a participant in the DOE decision for …

Synthetic Hydrogel As An Artificial Vitreous Body. A One-Year Animal Study Of Its Effects On The Retina, T. V. Chirila, I. J. Constable, Y. Hong, S. Vijayasekaran, M. F. Humphrey, P. D. Dalton, S. G. Tahija, M. A. L. Maley, M. J. H. Cuypers, C. Sharp, S. R. Moore, M. J. Davies

Cells and Materials

A hydrogel with a high water content was assessed in vitro and in vivo as a possible vitreous substitute. From a large series of polymers produced by the aqueous polymerization of methyl acrylamidoglycolate methyl ether (MAGME), a gel synthesized in 80% water was selected for an animal study. The gel was injected intravitreally into rabbit eyes and followed clinically by ophthalmoscopy, tonometry, and fundus photography. The gel was clinically well tolerated, but after 6 months ophthalmoscopy revealed progressive pallor of the optic nerve head. The eyes were enucleated one year after injection of polymer. Histopathological examination by light microscopy of …

Three-Dimensional Morphology And Platelet Adhesion On Pyrolytic Carbon Heart Valve Materials, S. L. Goodman, K. S. Tweden, R. M. Albrecht

Cells and Materials

Low-temperature isotropic pyrolytic carbon (LTIC) is the preferred material for mechanical heart valve prosthetics due to its durability and good thromboresistance, although thromboembolic complications remain a significant clinical problem. LTlC morphology has been previously studied using scanning (SEM) and transmission electron microscopy (TEM), and scanning tunneling microscopy (STM). However, these microscopies have limitations with imaging rough surfaces. In this study, LTIC valve leaflets from CarboMedics, Inc. and St. Jude Medical, Inc. were prepared and polished exactly as used in clinical prosthetics, and examined at magnifications up to macromolecular resolution using stereo-pair low-voltage SEM (LV -SEM). LV -SEM reveals that LTIC …

Surface Recombination Velocity And Bulk Carrier Lifetime Measurement Of Silicon Crystals By Using Photoluminescence Time Decay, Karsten Thölmann, Masakazu Yamaguchi, Akihiro Yahata

Scanning Microscopy

The time decay for photoluminescence (PL) emitted from silicon crystals has been used to obtain both bulk carrier lifetime (Tb) and surface recombination velocity (S). Experimental results were interpreted with the assumptions that the sample was under a low-excitation condition and that the ratio of radiative to non-radiative recombination rates was constant throughout the carrier decay process. Analysis was applied to several wafers covered with different kinds of silicon dioxide (SiO₂). The results indicate that PL time decay measurement is effective to obtain the values of Tb and S.

Scanning Tunneling Microscope-Induced Luminescence Spectroscopy On Semiconductor Heterostructures, M. Pfister, M. B. Johnson, U. Marti, S. F. Alvarado, H. W. M. Salemink, D. Martin, F. Morier-Genoud, F. K. Reinhart

Scanning Microscopy

Scanning tunneling microscope (STM)-induced luminescence is explored as a technique for the characterization of semiconductor quantum wells and quantum wire heterostructures. By injecting minority carriers into the cleaved cross section of these structures, luminescence excitation on a nanometer scale is demonstrated. Using spectrally resolved STM-induced luminescence for the tip placed at various positions across the cleaved heterostructure, it is possible to obtain local spectroscopic information on closely spaced quantum structures.

Interpretation Of Cathodoluminescence Spectra Obtained From Dolomite And Calcite Gangue Minerals, And Dolostone Breccias In The Central Tennessee Zinc District (U.S.A.), Otto C. Kopp, E. Loren Fuller Jr., Michael R. Owen

Scanning Microscopy

Spectral patterns were obtained for zoned dolomite and unzoned calcite gangue, and dolostone breccia fragments from the Right Fork area in the central Tennessee zinc district (U.S.A.). The samples had been analyzed previously for Fe, Mn, and other trace elements using a synchrotron XRF probe. Spectra were obtained for zoned dolomite, breccia fragments, and unzoned calcite using an ELM2-B cold-cathode Luminoscope attached to an Oriel Multispec Compact Spectrograph. Spectra obtained for the prominent dolomite zones, which luminesce medium-bright to bright red to the eye, revealed a broad peak in the vicinity of 460 nm and a more intense peak in …

Treaties, Spirituality, And Ecosystems, American Indian Interests In The Northern Intermontane Region Of Western North America, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

As a contribution to the Interior Columbia Basin Ecosystem Management Project, this report provides an introduction to current American Indian interests in the northern intermontane region of western North America and assesses the prospects of tribes pursuing those interests into the 21st century. A primary goal of the Federal interagency project is to develop scientifically sound and ecosystem-based management strategies for forest and range lands under stewardship of the Forest Service and Bureau of Land Management in the greater Pacific Northwest (Fig. 1). As an integral part of the project, a scientific assessment is designed to characterize and assess socio-economic …

Draft Environmental Impact Statement, Oil And Gas Leasing On Lands Administered By Dixie National Forest, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

This Environmental Impact Statement documents the analysis of the potential effects of implementing each of five alternatives for management of the Federal oil and gas estate on lands administered by the Dixie National Forest in Garfield, Kane, Iron, Washington, Piute, and Wayne Counties, Utah. The existing condition of the environmental resources in the project area is documented and potential impacts to those resources as a result of implementing the proposed action are addressed. The alternatives are Proposed Action - Forest Plan Intent, (1) No Action - No Lease, (2) Forest Plan Modification A, (3) Forest Plan Modification B, (4) Forest …

Draft Special Resource Study And Environmental Assessment, United States Department Of Interior National Park Service

All U.S. Government Documents (Utah Regional Depository)

One of the responsibilities of the National Park Service is to identify nationally significant natural, cultural, and recreational resources and assist in their preservation both inside and outside the national park system. The areas managed by the National Park Service are only one part of a national inventory of special and protected areas managed by innumerable federal, state, and local agencies and the private sector. Consequently, addition to the national park system is only one of many alternatives for ensuring the preservation of significant national resources for public enjoyment and benefit. As such, the purpose of this study is to …

Department Of Energy Programmatic Spent Nuclear Fuel Management And Idaho National Engineering Laboratory Environmental Restoration And Waste Management Programs Final Environmental Impact Statement, Volume 2, Part B, United States Department Of Energy

All U.S. Government Documents (Utah Regional Depository)

Per U.S. Environmental Protection Agency's guidance, each contaminant was categorized as carcinogenic or noncarcinogenic. Exposures to contaminants were then evaluated for potential health effects. The method used was dependent on whether the exposure was to the public or to a worker and whether the contaminant was classified as a carcinogen or a noncarcinogen. Health effects were reported separately and were not summed where distinctly different types of effects were reported for chemical exposures (that is, carcinogenic and noncarcinogenic).

Strutting Sounds And Strutting Posturing Of Two Utah Sage Grouse Populations, United States Department Of Agriculture, Forest Service

Wildlife Conservation and Management

Sound and video tape recordings and still pictures were taken of two populations of strutting male sage grouse (Centrocercus urophasianus). The two populations studied were from the Strawberry Valley and Parker Mountains. Sixteen elements of sounds were identified in the strutting sequence. These elements were the same for both populations. Video tape and still picture analysis revealed that both populations were similar in posturing during the strutting sequence. We concluded that the Parker Mountains sage grouse population is suitable in terms of breeding display behavior to augment the Strawberry Valley population. Sexual compatibility would need to be determined in future …

Jackson Hole Cooperative Elk Studies Group, Grand Teton National Park, 1995 Annual Report, United States Department Of The Interior, National Park Service

Wildlife Conservation and Management

A modelling effort using POP-II software was presented to show the effects of altering the harvest structure of the reduction. The relatively high harvests of the last two years may result in maintaining the current Park population levels. A variety of scenarios increasing the number and proportion of cows harvested show the greater effects cow harvests have on reducing the population relative to bull harvests.

Assuring A Long Term Groundwater Supply: Issues, Goals And Tools, Richard C. Peralta

All Archived Publications

No abstract provided.

Applying Fundamentals Of Wildfire Management To Improve Noxious Weed Control, Steven A. Dewey

All Archived Publications

No abstract provided.

Utah's Grazing Lands: Sustaining A Vital Resource, Utah State University Extension

All Archived Publications

No abstract provided.

Nps Educational Directory, Kathryn L. Farrell-Poe

All Archived Publications

No abstract provided.

Three-Dimensional Thermoluminescence Spectra And Their Application In The Study Of Some Sedimentary Quartz, J. R. Prescott, R. B. Scholefield, A. D. Franklin

Scanning Microscopy

The intensity of thermoluminescence emission is a function of both temperature and photon energy (or wavelength) and therefore lends itself to a three-dimensional (3-D) display, either in the form of an isometric plot or a contour diagram. The technique of 3-D thermoluminescence spectrometry is briefly reviewed and the advantages and applications are illustrated by reference to the spectral properties of samples of Australian sedimentary quartz drawn from the context of thermoluminescence dating. In this context, the temperature of emission, the photon energy and the ease with which the emission is bleachable by sunlight are of significance. It is suggested that, …

Bta Oil Producers Bravo Field Development, Green River Resource Area, Environmental Assessment, United States Department Of The Interior Bureau Of Land Management

Environmental Assessments (WY)

This Environmental Assessment (EA) was prepared to evaluate and disclose potential environmental impacts associated with the Bravo field development proposed by BTA Oil Producers and its partners (BTA) in Sweetwater County, Wyoming. BTA has tested and confirmed the existence of substantial quantities of natural gas on Federal oil and gas leases within its Bravo Unit and on adjacent lands (hereafter referred to as the "development area"). BTA would like to proceed with development of its existing oil and gas leases and other developments necessary to serve future oil and gas production. BTA would be assisted in this effort by contractors …

Texaco's Stagecoach Draw Unit Final Environmental Impact Statement, Sweetwater County, Wyoming, United States Department Of The Interior Bureau Of Land Management

Final Environmental Impact Statements (WY)

This abbreviated Final Environmental Impact Statement (FEIS) on the Texaco Stagecoach Draw Unit natural gas development project, located approximately 7 miles southwest of Farson, Wyoming, on Wyoming Highway 28, is provided for your information and use. This FEIS is a supplement to the Draft Environmental Impact Statement (DEIS), published March 10, 1995, and contains the following material: it incorporates by reference the material presented in the DEIS and identifies the changes to the DEIS required as a result of additional information and public comment subsequent to publishing of the DEIS; comments received on the DEIS; and responses to the comments. …

Final Jackpot Mine Project Environmental Impact Statement, United States Department Of The Interior Bureau Of Land Management

Final Environmental Impact Statements (WY)

This Final Environmental Impact Statement (FEIS) assesses the environmental consequences of a proposed uranium mine project in Fremont and Sweetwater Counties, approximately 14 miles southeast of Jeffrey City, Wyoming. This FEIS incorporates by reference most of the material presented in the Draft Environmental Impact Statement (DEIS) for the Green Mountain Mining Venture (GMMV), Jackpot Mine Project, and is designed to be used with the DEIS. Copies of the DEIS are available from the BLM Lander Resource Area at P.O. Box 589, Lander, Wyoming, 82520.

Cathodoluminescent Properties Of Single Crystal Materials For Electron Microscopy, Rudolf Autrata, Petr Schauer

Scanning Microscopy

The results of measurements of cathodoluminescence efficiencies, decay characteristics and emission spectra of YAG:Ce, YAP:Ce, P47 (Y₂SiO₅:Ce) and CaF₂:Eu single crystals at excitation by electrons with an energy of 10 keV and a current density of the order of 10^-8 A cm^-2 are presented. Advantages and disadvantages of the individual single crystals intended for application in electron microscopes are dealt with. Attention is paid to the photomultiplier tube (PMT) matching, degradation and afterglow of the mentioned single crystals. For YAG:Ce, the effect of the activator concentration of crystals and the effect of …