Life Sciences Commons^™

Scanning Electron Microscopic Observation Of Dark Cells After Streptomycin Perfusion Of The Vestibule In Guinea Pigs, Xianxi Ge, John J. Shea Jr.

Scanning Microscopy

Hearing has been stabilized in the majority of patients studied in the treatment of Meniere's disease with streptomycin. This observation suggests that effects of streptomycin may ameliorate endolymphatic hydrops, possibly by attenuating the activity of secretory tissue. The purpose of this study is to observe the dark cells of the utricle in guinea pigs after streptomycin perfusion of the vestibule. Twelve pigmented guinea pigs weighing 250-350 grams were used in this study. The vestibules in five guinea pigs were perfused monolaterally with 150 μg of streptomycin in artificial perilymph and, in seven, the vestibules were perfused only with artificial perilymph …

Gold Coating Of Respiratory Cilia For Scanning Electron Microscopy, E. Toskala, J. Nuutinen, M. Rautiainen, A. Pelttari

Scanning Microscopy

The optimal thickness of gold coating of cilia for scanning electron microscopy was studied using respiratory mucosa obtained from pigs. We tested 8 different coating times, from 10 seconds to 4 minutes, which resulted in gold layer thicknesses varying from 16 ± 1 nm to 100 ± 3 nm. The thickness of the gold layer with a coating time of 60 seconds and voltage of 2.5 kV was 43 ± 5 nm. This thickness of gold layer gave good image quality without causing any electric charging. With thinner gold films, the amount of electric charging increased. When the coating time …

Swift Heavy Ion Induced Electron Emission From Solids, Hermann Rothard

Scanning Microscopy

Quite a number of experiments have been performed on electron emission from solids induced by slow (projectile velocity Vp < 1 atomic unit) or medium velocity heavy ions (projectile energy Ep < 1 MeV/u). Only a few experiments have been made with fast heavy ions (projectile atomic number Zp > 8, Ep > 2 MeV/u) concerning either electron emission yields -y, or double differential electron energy spectra d2n(0)/dEd0 as a function of the observation angle 0. We present the results obtained so far on electron emission induced by fast (Ep > 2 MeV/u) heavy ions (Zp ~ 6). Topics discussed include experimental results for electron yields, -energy and -angular distributions and channelling phenomena as well as the theoretical approaches. We also present new results from recent studies on the evolution of electron yields …

Semiquantitative Analysis By Scanning Electron Microscopy Of Cochlear Hair Cell Damage By Ototoxic Drugs, Takehisa Saito, Yasuhiro Manabe, Noriyuki Honda, Takechiyo Yamada, Takehito Yamamoto, Hitoshi Saito

Scanning Microscopy

The ototoxicity of cisplatin and carboplatin in the organ of Corti of the guinea pig was evaluated semiquantitatively. Damage of the stereocilia of outer hair cells (OHCs) observed by scanning electron microscopy (SEM) was classified into normal, grade 1 (10-50% loss of stereocilia), grade 2 (less than 50% remaining stereocilia), or grade 3 (missing stereocilia). The OHCs observed by light microscopy (LM) were classified as remaining or missing cells. Fifty OHCs of each row in the middle part of each turn of the cochlea were counted (a total of 150 cells per turn). Guinea pigs were administered 5 mg/kg of …

Comparison Of Cell Sediment And Surface Grown "Test Plaque" Using Scanning Electron Microscopy, S. M. Mccormack, C. M. D. Maran, K. M. Scott-Anne, D. T. Zero

Scanning Microscopy

Scanning electron microscopy was used to compare the morphology, integrity and distribution of bacterial cells in a test plaque grown on the surface of enamel with that of the cell sediment plaque routinely used in a short-term intraoral caries model. Cultures of S. mutans IB-1600 or S. sobrinus 6715-13 were grown in complex media supplemented with either 2.0% sucrose (glucan plaque) or 0.2 % glucose (non-glucan plaque). Cell sediment (CS) plaque was prepared by centrifuging the cultures after incubation, recovering the cell sediment, and spreading it on Metricel membrane filter paper. Surface grown (SG) plaque was prepared by suspending saliva-coated …

Effect Of Sodium Saccharin On The Neonatal Rat Bladder, Samuel M. Cohen, Martin Cano, Margaret K. St. John, Emily M. Garland, Mohamad Khachab, Leon B. Ellwein

Scanning Microscopy

In a two-generation bioassay, high doses of dietary sodium saccharin (NaSac) produce bladder carcinoma in rats, whereas acid saccharin (HSac) does not effect the urothelium. NaSac and HSac administered as 5% of the diet to F0 Sprague-Dawley (SD) and F344 rats, continued through to the weaned male rats for ten additional weeks. Control 3H-thymidine labeling index (LI) was high prior to and at birth (approximately 11%), declining rapidly by weaning (to < 0.2). Neither NaSac nor HSac increased proliferation through 7 days of age. NaSac increased the proliferation rate at later times, whereas HSac did not. The LI decreased to control levels in NaSac-fed rats switched to control diet after weaning and increased in control-fed rats switched to NaSac after birth or weaning. In a second experiment, 5% NaSac did not affect urothelial morphology of SD rats through 7 days. By 21 days post-birth, urothelial hyperplasia occurred in NaSac-fed rat. The LI in treated versus control was similar through gestation, with a slight difference by 7 days. LI was significantly different by 21 days post-birth, but was similar between males and females. These results provide additional evidence for the increased cell proliferative effects of NaSac during the neonatal period, but not during gestation.

Three-Dimensional Configuration Of Crypts Of Different Types Of Colorectal Adenomas, Keijiro Araki, Takuro Ogata

Scanning Microscopy

The three-dimensional configuration of isolated crypts of normal human colonic mucosa and colorectal adenomas was examined by scanning electron microscopy. For isolation of the crypts, the digestion method with HCl was used for formalin fixed tissues, and the separation method with ethylenediaminetetraacetic acid (EDT A) following ultrasonication was applied to fresh tissues. In a comparative study, the NaOH cell-maceration method, which visualized the sub-basal laminal collagen sheath, was applied. The isolated crypts from the normal colon were visualized as a single straight tubule resembling a test tube. Most isolated crypts of the tubular adenomas were visualized as elongated fan-like structures …

Etiology Of Calcium Oxalate Nephrolithiasis In Rats. Ii. The Role Of The Papilla In Stone Formation, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, R. De Water, J. C. Romijn, C. F. Verkoelen, L. C. Cao, J. M. Van 'T Noordende, F. H. Schröder

Scanning Microscopy

In kidneys of healthy rats submitted to a crystal-inducing diet (CID) with ethylene glycol (EG) and NH₄Cl, the fate of retained crystals in the papillar region is studied during a recovery period of one, five or ten days, as model system for human nephrolithiasis. Scanning electron microscopy (SEM) shows, at papillary tips bulging into the calycine space, crystal masses covered either by the epithelium or a thin fibrous veil, or by unidentified mobile cuboidal cells. After CID plus one or five days recovery, small sub-epithelial swellings are seen of large sub-epithelial crystals at or around the papillary tip. …

Etiology Of Calcium Oxalate Nephrolithiasis In Rats. I. Can This Be A Model For Human Stone Formation?, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, R. De Water, J. C. Romijn, C. F. Verkoelen, L. C. Cao, F. H. Schröder

Scanning Microscopy

Crystal retention is studied in a rat-model system as a possible mechanism for the etiology of human nephrolithiasis. A crystal-inducing diet (CID) of ethylene glycol plus NH₄Cl in their drinking-water is offered to healthy rats to generate intratubular crystals. Subsequently, the fate of retained crystals is investigated by allowing the rats a tissue recovery/crystalluria phase for three, five and ten days, respectively, on normal drinking water.

The process of exotubulosis is observed in cortex and medulla of aldehyde-fixed kidneys after three days recovery. After five days, crystals are predominantly seen there in the interstitium. After ten days, cortex …

Cell Surface Changes Of Hemopoietic Cells During Normal And Leukemic Differentiation: An Immuno-Scanning Electron Microscopy Study, D. Soligo, E. P. De Harven, N. Quirici, L. Caneva, G. Lambertenghi Deliliers

Scanning Microscopy

Hemopoietic cells display a wide range of cell surface antigens which are either lineage specific or acquired during differentiation. Monoclonal antibodies can be used, in conjunction with colloidal gold markers, to identify under the scanning electron microscopy (SEM) at the single cell level, specific lineage or maturation stages in the hemopoietic bone marrow. Normal bone marrow cells, either gradient separated or purified by immuno-magnetic methods and leukemic cell samples, which can be considered as "frozen" stages of hemopoietic differentiation, have been studied with this method. Typical cell surface morphologies, which characterize immature progenitor cells and cells committed or differentiated towards …

Notes On The Microstructure Of The Nautilus Shell, P. R. Mitchell, P. P. Phakey

Scanning Microscopy

The shell of the Nautilus was examined using scanning electron microscopy, transmission electron microscopy and polarized light microscopy. The structure consisted of two major layers: a porcellaneous outer layer and a nacreous inner layer. Most of the porcellaneous layer was composed of granular crystals randomly distributed with a substructure suggestive of bundles of acicular crystallites. A separate prismatic sublayer of the porcellaneous material was composed of a more regular arrangement of crystals. The nacre was composed of alternating crystalline lamellae and films of organic material. The lamellae were formed of many polygonal crystal platelets. The growth surface of the nacre …

Investigation Of Nanoparticles In High Resolution Scanning Electron Microscopy (Sem) And Low Voltage Sem By Digital Image-Analysis, B. Ocker, R. Wurster, H. Seiler

Scanning Microscopy

Small particles (Cu, Ag, In, Sn, Au, also MgO and NaCl) were prepared in the diameter range from 1 nm to 100 nm on different conductive substrates by thermal evaporation in high-vacuum or in an inert gas atmosphere. Imaging of the particles was performed in a high resolution scanning electron microscope (HRSEM) that can also be operated at low beam voltages of a few hundred volts. This mode of operation is called low voltage SEM (LVSEM). Scanning electron micrographs were taken at different beam voltages V_O (0.5-30 kV). The micrographs were digitally recorded and analyzed with an image processing …

High Resolution Electron Microscopy Of Enamel Crystallites Demineralized By Initial Dental Caries, Yoshihiko Hayashi

Scanning Microscopy

Acids produced by various oral bacteria cause mineral loss and crystallite dissolution during the development of enamel caries. In order to demonstrate this phenomenon, the initial disappearance of lattice fringes and the formation of a central perforation in crystallites were examined by high resolution electron microscopy (HREM) in initial enamel caries without macroscopic tissue evidence of destruction. Ultrathin sections were also examined by selected area electron diffraction to reveal the mineral phase of the surface layer in carious enamel.

A marked variation in the dissolution pattern was disclosed in the initial carious lesions. HREM revealed that disappearance of the lattice …

Controlling Influence Of Phosphocitrate In Vitro And In Vivo On Calcium Oxalate Crystal Formation And Growth, John D. Sallis, Nathan F. G. Parry, John D. Meehan, Harold Kamperman, Maree E. Anderson

Scanning Microscopy

Calcium oxalate (CaOx) crystallization in the presence of phosphocitrate (PC) was studied by both in vitro and in vivo techniques. Crystals of the monohydrate (COM) and the dihydrate (COD) forms were generated under controlled conditions in a silica gel matrix. Our data indicated only COD crystals formed when PC was present, inferring that the COD to COM transformation was being impeded. COD crystals were smaller in size than controls and there was evidence of interpenetral twinning. An in vivo study using a rat bladder implant model noted similar findings. Scanning electron microscopy (SEM) revealed that implants recovered from PC treated …

Revascularization Of An Excisional Wound In Gingiva And Oral Mucosa. A Scanning Electron Microscopic Study Using Corrosion Casts In Rats, Nils J. Selliseth, Knut A. Selvig

Scanning Microscopy

The purpose of this study was to examine microvascular regeneration associated with gingival wound healing. A full-thickness piece of gingiva and oral mucosa was excised along the palatal aspect of the right maxillary first and second molars in 20 young Wistar rats. The contralateral side served as unoperated control. After 2, 4, 7, 10 or 20 days of healing, microvascular corrosion casts were produced and examined by scanning electron microscopy. At 2 days, vessels surrounding the wound were dilated and impressions representing sites of leukocyte margination were prominent in the walls of venules. Capillary buds were emerging from venules and …

Scanning Electron Microscopy And Transmission Electron Microscopy Aspects Of Synergistic Antitumor Activity Of Vitamin C - Vitamin K3 Combinations Against Human Prostatic Carcinoma Cells, Jacques Gilloteaux, James M. Jamison, Meenaxi Venugopal, David Giammar, Jack L. Summers

Scanning Microscopy

A MTT/formazan assay was used to evaluate the antitumor activity of vitamin C (Vit C), vitamin K₃ (Vit K₃), or vitamin C:vitamin K₃ combinations against a human prostatic carcinoma cell line (DU145). Both Vit C and Vit K₃ alone exhibited antitumor activity, but only at elevated doses. When Vit C and Vit K3 were combined at a C:K₃ ratio of 100:1 and administered to the carcinoma cells, the 50% cytotoxic concentrations (CD50) of the vitamins decreased 10-to 60-fold. Subsequently, the DU145 cells were examined with transmission and scanning electron microscopy (TEM and SEM) following …

Experimental Calcium Oxalate Nephrolithiasis And The Formation Of Human Urinary Stones, Saeed R. Khan

Scanning Microscopy

Calcium oxalate nephrolithiasis in rats requires induction of hyperoxaluria which results in increased urinary calcium oxalate supersaturation. As a result of low to mild chronic hyperoxaluria, calcium oxalate crystals deposit first in the papillary collecting ducts. Crystal deposition in the kidneys is preceded by calcium oxalate crystalluria and starts with the retention of aggregated calcium oxalate crystals in the renal tubules. Retained crystals move from the tubules to the interstitium, and in the process, become anchored to the tubular basement membrane. Crystal aggregates present in the superficial peripheral collecting ducts of the renal papillae ulcerate through to the papillary surface …

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.

Cathodoluminescence Of Rare Earth Doped Zircons. I. Their Possible Use As Reference Materials, F. Cesbron, P. Blanc, D. Ohnenstetter, G. Rémond

Scanning Microscopy

Synthetic zircon crystals (ZrSiO₄), undoped and doped with Y³⁺, La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺, Lu³⁺, were grown from a flux consisting of a mixture of Li₂MoO₄ and MoO₃ heated to 1125°C and then cooled to 750°C. The cathodoluminescence (CL) spectra of these zircons were analyzed at room-temperature and near liquid nitrogen temperature with a CL spectrometer …

A New Model Of Low Temperature Photoluminescence In Amorphous Semiconductors, Mathieu Kemp, Marvin Silver

Scanning Microscopy

Recent low temperature a-Si:H photoluminescence experiments show the presence of two peaks in the lifetime distribution, and a dependence of the efficiency on generation rate. These results contradict every existing model of amorphous semiconductor photoluminescence. The reason for the discrepancy is that every model predicts diffusive motion of the photo-generated pairs. We show how the inclusion of coulomb interaction between photocarriers, spin selection effects, and Auger recombination gives back agreement of theory with experiment. This new picture of the phenomenon also explains the transient behavior of the luminescence intensity.

Cathodoluminescence Of Carbonates: New Applications In Geology And Archaeology, V. Barbin

Scanning Microscopy

Several new applications of cathodoluminescence (CL) have been developed during the last few years, including: combined CL imaging and/or spectroscopy and CL observations of carbonates previously considered to be non-luminescent or of minor interest. Basically, two previously unstudied types of carbonates were investigated: marbles, and recent shells. From numerous classical white marble samples, cathodomicrofacies were defined and described. A single cathodomicrofacies is generally characteristic of a given area. This finding permits identification of the source of white marbles and has been successfully applied to ancient marbles from different collections. Despite the well established idea that CL in biogenic carbonates is …

Luminescence Spectroscopy Of Semiconductor Surfaces And Interfaces, L. J. Brillson, S. Chang, A. D. Raisanen, I. M. Vitomirov

Scanning Microscopy

Low energy cathodoluminescence spectroscopy (CLS) employing incident electron energies in the range of a few kV or less enable measurement of electronic structure near semiconductor surfaces and interfaces. Coupled with photoluminescence spectroscopy (PL), the CLS technique has been extended to characterize electronic structure tens of nanometers below the free surface at metal-semiconductor and semiconductor-semiconductor junctions. CLS has revealed discrete, deep electronic states for clean and metallized semiconductor surfaces as a function of atomic ordering as well as vicinal surfaces as a function of misorientation. A combination of CLS and PL reveals deep level features associated with strain relaxation and dislocations …

Luminescence From Porous Silicon, Yasunori Mochizuki

Scanning Microscopy

Structural and optical properties of porous Si are reviewed with the main emphasis on the radiative recombination mechanisms. Behaviors of the visible photoluminescence and another intense luminescence process (the infrared luminescence) are discussed based on the available data provided by photoluminescence and related techniques. It is demonstrated that a further insight into the interrelation of these luminescence processes can be obtained by the optically-detected magnetic resonance method, in which non-radiative point defects (surface dangling bonds) are used as a local structural probe for the radiative states.

As for the model for the visible light emission, the implication of the quantum …

Diamond Luminescence, R. Heiderhoff, L. J. Balk

Scanning Microscopy

Luminescence spectroscopy is an established tool to investigate natural, high pressure synthesized, and chemical vapour deposited (CVD) diamond. The spectral range extends from 5.3 eV in the ultraviolet to approximately 1.2 eV in the near-infrared. More than 100 optical centres have been observed.

Since the early 1930's, semiconducting diamond for electronic devices has been of interest to science. The large bandgap (5.5 eV), low dielectric constant (5.7), and high thermal conductivity (about 5 times larger then that of Ag), as well as the superior charge-carrier transport properties, such as electron and hole mobility (µ^-: 2200 cm²/Vs, …

Cathodoluminescence Of Some Synthetic Calcite Crystals. Investigation On The Role Played By Cerium, Rémy Chapoulie, Françoise Bechtel, Daniel Borschneck, Max Schvoerer, Guy Rémond

Scanning Microscopy

Cathodoluminescence (CL) from undoped and cerium-doped synthetic calcite is examined at room temperature and at liquid nitrogen temperature, using a scanning electron microscope. At room temperature, all of the samples exhibit a CL emission in the near ultra-violet (UV), centered at approximately 370 nm with some possible shoulders at 345 nm. At low temperature, the samples show an emission of CL in the near UV but with two well defined maxima for the Ce-doped crystals (460 ppm and 4600 ppm) peaking at 345 and around 380 nm. The third Ce-doped crystal (1.74%) presents a maximum at 375 nm and a …

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, …

Temperature-Dependent Cathodoluminescence Spectroscopy And Microscopy As A Tool For Defect Identification In Semiconducting Ceramics: Application To Batio3 Ceramics, T. Hübner, U. Marx, J. Schreiber

Scanning Microscopy

Cathodoluminescence (CL) spectroscopy and microscopy were applied to investigate the characteristic grain-boundary contrast in semiconducting ferroelectric BaTiO₃ ceramics. It was shown, that "chemically clean" grain boundaries do not reveal any specific CL components neither in the visible nor in the infrared part of the spectrum. Instead, the contrast arises from at least two different non-radiative recombination centers present in the grain and the grain-boundary zones, respectively. Activation thresholds for these centers were determined from the temperature dependence of the integral CL signal down to 30K. The different values found explain the contrast reversal observed in BaTiO₃ ceramics upon …

Can Photo- And Cathodoluminescence Be Regarded As Complementary Techniques?, S. Myhajlenko, R. A. Puechner, J. L. Edwards, D. B. Davito

Scanning Microscopy

Photoluminescence (PL) usually provides macroscopic, high quality spectroscopic data. Cathodoluminescence (CL), on the other hand, offers the same information with microscopic imaging. However, replicating PL signatures in a CL system is not straightforward since matching experimental conditions, such as temperature and excitation density, is difficult. The matter is further exacerbated by inherent differences in the nature of excitation: electrons versus photons. Our work with high purity semiconductors suggests that CL is generally more sensitive to excitation "circumstance" than PL. For example, electrons can cause sample charging and contamination-related phenomena that dramatically affect CL. Changes in surface attributes (e.g., by chemical …

Thermoluminescence Of Zircon, Philibert Iacconi

Scanning Microscopy

The thermoluminescence (TL) of synthetic zircons into which some impurities have been individually insert-ed is investigated. The results obtained show that, after X-irradiation at 77K, the synthetic zircons present three kinds of thermoluminescent emissions. The first is related to the OH^- ions, the second is typical of the SiO₄^4-groups, and the third is characteristic of RE³⁺ ions with RE = Dy, Tb, Gd, Eu, or Sm (RE = rare earth).

The OH^- emission is a large band at 285 nm which appears at 115 and 160K.

The SiO₄^4- TL emission consists of …

Advances In Research Of Defects In Quartz Based On Luminescence, A. Halperin

Scanning Microscopy

The first part of this paper reviews the observation of the unconventional thermoluminescence {TL(M), where M = Li or Na} peaks observed in the glow curve of Li-and Na-containing quartz, and describes the full solution of the puzzling effect of the TL(M) peaks which needed a two irradiation procedure for their formation. Of interest is the intermediate warming (IW) method, which consisted of two irradiations and warming of the sample to 150-300 K between the two irradiations. This was explained as follows: the first low temperature irradiation produces {AlO₄/M/h}⁺ centers, when the now loosely bound M ions …