bluuebunny/crossref_metadata_2025_split huggingface dataset:
High resolution and image processing of otoconia matrix
Authors: Fermin C. D. 
Published: February 2005

AbstractThis study was designed to investigate patterns of fibrils organization in histochemically stained otoconia. Transmission electron microscope and video imaging were used. These data indicate that otoconia of the chick (Gallus domesticus) inner ear may have central cores in vivo. The data also show that the ultrastructural organization of fibrils fixed with aldehydes and histochemical stains follows trajectories that conform to the hexagonal shape of otoconia. These changes in direction may contribute to the formation of a central core. The existence of central cores is important for the in vivo buoyancy of otoconia. Packing of fibrils is tighter after phosphotungstic acid (PTA) stained otoconia than with other histochemical stains, which usually produce looser packing of fibrils and seemingly larger central core. TEM of tilted and untilted material showed that turning of fibrils occurs at the points where the face angles of otoconia form and where central cores exist. Video image processing of the images allowed reconstructing a template which, if assumed to repeat and change trajectories, would fit the pattern of fibrils seen in fixed otoconia. Since it is highly unlikely that aldehyde primary fixation or PTA stain caused such drastic change in the direction of fibrils, the template derived from these results may closely approximate patterns of otoconia fibrils packing in vivo. However, if the above is correct, the perfect crystallographic diffraction pattern of unfixed otoconia do not correspond to patterns of fixed fibrils. © 1993 Wiley‐Liss, Inc.
A simplified mode of differential phase contrast lorentz microscopy
Authors: Kraut S. , Cowley J. M. 
Published: February 2005

AbstractA simplified mode of differential phase contrast Lorentz microscopy for the study of magnetic domain structures in thin films is proposed and demonstrated. This mode employs a single annular detector in a scanning transmission electron microscope rather than the specialized split detectors that have been previously used. The resulting signal is sufficiently linear with magnetic field strength to allow quantitative data to be obtained on the domain configurations and the natures of the domain walls. © 1993 Wiley‐Liss, Inc.
A novel method for the cross‐sectional TEM preparation of thin films deposited onto water‐soluble substrates
Authors: Sáfrán György , Panine Pierre 
Published: February 2005

AbstractA preparational method was developed solving the problem of cross‐sectional TEM preparation of thin films and layer systems deposited onto water‐soluble substrates. The technique is based on the replacement of the sample onto steady substrate, followed by mechanical and ion beam thinning. Cross‐sectional TEM micrographs of Ag and Ag/Ag2Se layers are shown presenting the efficiency of this novel technique. © 1993 Wiley‐Liss, Inc.
Cracking in albumen photographs: An ESEM investigation
Authors: Messier Paul , Vitale Timothy 
Published: February 2005

AbstractThe preservation of nineteenth‐century albumen prints is of great concern to collection managers and to conservators of photographic materials. In the field of art conservation, preservation techniques incorporating aqueous treatments are often used to enhance the long‐ and short‐term stability of historical artifacts or art objects. In a study of the interaction of water with albumen photographs, experiments were carried out in the ESEM to follow the real time effects of water on the prints. The experiments were designed to observe the effects of a range of relative humidities and liquid water on samples of expendable historic albumen prints, utilizing the advantages of imaging in the presence of water vapor. All albumen photographs exhibit a fine network of cracks in the albumen protein layer. Average crack width is approximately 10 μm. As observed in the ESEM, a 4.25‐fold increase in the width of a single crack (at 50% RH), viewed normal to the surface, resulted from a single controlled excursion to high relative humidity and immersion. In an extraordinary series of images, a print viewed in cross‐section exhibited a 22% swelling and shrinkage in thickness, and a 5% and 9% swelling and shrinkage along the width of a fragment of the albumen/image layer when the sample was immersed in water and dried. The visual information gained through the use of the ESEM helped to focus a materials investigation and served as a foundation for a study which shows that aqueous treatment causes increased cracking of both unsupported albumen and the albumen/image layer in prints. © 1993 Wiley‐Liss, Inc.
Morphology of nitric acid and water ice films
Authors: Keyser Leon F. , Leu Ming‐Taun 
Published: February 2005

AbstractIce films have been used to simulate stratospheric cloud surfaces in order to obtain laboratory data on solubilities and heterogeneous reaction rates. To obtain intrinsic uptake and surface reaction probabilities which can be applied to atmospheric models, it is necessary to carefully characterize these films. In the present study, environmental scanning electron microscopy (ESEM) is used to study thin films of both water ice and nitric acid ice near the composition of the trihydrate. The ices are formed by vapor deposition onto aluminum or borosilicate‐glass substrates cooled to about 200 K. Micrographs are recorded during the deposition process and during subsequent annealing at higher temperatures. The results show that the ice films are composed of loosely consolidated granules, which range from about 1 to 20 μm in size at temperatures between 197 and 235 K. Cubic water ice is sometimes observed at 200 K and converts to the hexagonal form at slightly higher temperatures. The loose packing of the granules confirms the high porosities of these films obtained from separate bulk porosity measurements. Average surface areas calculated from the observed granule sizes range from about 0.2 to 1 m2 g−1 and agree with surface areas obtained by gas‐adsorption (BET) analysis of annealed ice films. For unannealed films, the BET areas are about an order of magnitude higher than the ESEM results and imply that the unannealed ices contain microporosity which is lost during the annealing process. The present results have important implications for the extraction of intrinsic reaction probabilities from laboratory rate data. © 1993 Wiley‐Liss, Inc.
Oil sorption behavior of various sorbents studied by sorption capacity measurement and environmental scanning electron microscopy
Authors: Choi Hyung‐Min , Moreau Jerry P. 
Published: February 2005

AbstractOil sorption capacities of various natural and man‐made fibrous sorbents were compared in a simulated seawater bath containing oil. Natural sorbents such as milkweed, kapok, cotton, and wool showed higher sorption capacities than man‐made sorbents such as polyester, polypropylene, viscose rayon, nylon 6, nylon 66, and acetate. Sorption capacities of the natural sorbents were over 30 g oil/g fiber. No definite advantages were observed using man‐made bicomponent and biconstituent fibers over regular man‐made fibers with respect to their sorption capacity.Analyses of sorption mechanisms using an environmental scanning electron microscope revealed that an oil deposit disappeared from the fiber surface after a certain time interval in milkweed, kapok, and cotton. This suggested that the sorption of oil in these fibers occurred through capillary action, probably due to their hollow lumens. Contrarily, adsorption, a surface phenomenon, would be the most prominent mechanism for oil sorption of wool fibers due to large amounts of surface wax, irregular scaly surfaces, and crimp. Effects of both adsorption and absorption were shown in the oil sorption of man‐made fibers, depending upon the type and shape of the sorbent. Dumbbell‐like oil deposits were seen on the fiber surface in certain oleophilic man‐made fibers, because of a partial wetting of oil on the fiber surface. For some hydrophilic man‐made fibers such as polyvinylalcohol and copolymer of isobutylene‐maleic anhydride, the physical configuration of the fiber was a decisive factor in determining oil sorpton capacity of the sorbents. © 1993 Wiley‐Liss, Inc.
Proposed healing and consolidation mechanisms of rock salt revealed by ESEM
Authors: Hwang Chao Lung , Wang Ming Liang , Miao Shuke 
Published: February 2005

AbstractThe grain boundary healing behavior of crushed rock salt was mainly studied by employing the environmental scanning electron microscope (ESEM) to study the consolidation mechanism of rock salt backfill. Dedicated miniature round rock salt specimens were prepared for observation of the water trapping effect by using a cold stage in the ESEM to reach saturation conditions. Comparable high pressure pellets were prepared for measuring the crystal growth. Consolidation tests using materials made at different pressures and containing different moisture levels were conducted in order to construct the proposed mechanism. Direct observation of specimens in the ESEM resulted in viewing water trapped on the surface and the formation of a water meniscus between two particles. The concentration of brine at the grain boundary was observed as contributing to the amount of recrystallization. From aforementioned observations, a schematic drawing of the dissolution and recrystallization process may be redrawn. The amount of water therefore has a great effect on the consolidation of rock salt and is possibly due to the sliding, rotation, or crushing of the contact zone of the granular material. From such a study, tentative healing and consolidation mechanisms can be deduced. © 1993 Wiley‐Liss, Inc.
Examples of evolution of microstructure in ceramics and composites
Authors: Brown P. W. , Hellmann J. R. , Klimkiewicz M. 
Published: February 2005

AbstractIn this article we describe a number of studies involving the direct observation of microstructural evolution. In general these investigations were carried out to establish the mechanistic paths involved. The materials studied range from fibers being evaluated for use in high‐temperature ceramic composites to energetic materials used as propellants. In particular we discuss the room temperature imaging of materials difficult to image by conventional means and the use of the chamber atmosphere to influence microstructural evolution. Imaging of hydroxyapatite formed by chemical means is briefly described as an example of a difficult microstructure. Microstructural evolution during calcium aluminate cement hydration relies on the chamber atmosphere to control moisture loss from the hydrating specimens. In some instances microstructural evolution with heating occurred independently of the chamber atmosphere. Grain growth in PZT films formed by sol‐gel processes depends strongly on temperature but does not appear to depend on the chamber atmosphere. This is also the case for the combustion of nitroamine propellants in that their combustion does not depend on access to an external source of oxygen. In other studies, the chamber atmosphere played an indirect role in determining microstructure. However, the mechanistic path driving microstructural evolution in copper‐based inks used as conductive paths on electronic substrates is atmosphere dependent. These inks are formulated from copper powder, glass, and an organic binder, and the interaction of the binder with an oxidizing atmosphere allows it to be burned out before significant interaction occurs between the copper powder and the glass. Finally, the microstructural variations during the oxidation of structural composites at high temperature were used to allow assessments of their likely failure mechanisms. © 1993 Wiley‐Liss, Inc.
Application of ESEM to fluxless soldering
Authors: Koopman Nick 
Published: February 2005

AbstractThe ESEM is ideally suited to study soldering processes. We have used it to observe solder reflow and joining in ambient gases. It reproduces effects of atmospheric pressure reflow in a hot stage light microscope, but with much better clarity and depth of field. Compared to a regular SEM, the ESEM offers advantages of atmosphere control and ability to observe the solder samples without carbon or gold coating. These coatings could interfere with the oxidation/reduction reactions which occur at the solder/ambient gas interface. Very thin surface films, especially oxide layers dramatically influence the flow of liquid solder and the ability of solder to wet or join to another surface. Fluxless processes in particular are ideally suited for study in the ESEM. We have used the ESEM to observe dynamic fluxless soldering and have recorded events on videotape for later stop‐action still pictures and slow motion photography. Examples of these processes are shown to illustrate the ESEM capability. Included are solder deformation structure, balling reflow of eutectic solder in hydrogen, balling reflow of eutectic solder in nitrogen, joining of two solder disks in nitrogen, and dynamic melting and freezing of an off‐eutectic dendritic alloy. All of these are observed in the absence of flux. © 1993 Wiley‐Liss, Inc.
3D‐structure of cells of human salivary glands as seen by SEM
Authors: Riva Alessandro , Valentino Luigi , Lantini Maria Serenella , Floris Alessandra , Riva Francesca Testa 
Published: February 2005

AbstractTo demonstrate by SEM the topography and cytoarchitecture of the different parenchymal components of human salivary glands, we have employed a number of techniques that allow either the exposure of internal and lateral cell surfaces or, following the removal of connective tissue, the visualization of endpieces, ducts, and myoepithelial cells.Serous glands consist of indented acini attached to the ducts in a grape‐like fashion, whereas mucous and mixed glands are made up of smooth tubuli. Myoepithelial cells (mecs), which are abundant on the surfaces of acini, tubuli, and intercalated ducts, are sparse on striated ducts. They are star‐shaped on acini, striated ducts, and most of the tubuli. Spindle‐shaped mecs are seen, instead, on intercalated ducts and, occasionally, on mucous and mixed tubuli as well.Cells of striated ducts split into a number of large basal portions whose surface is covered by long laminated processes responsible for the striations seen with TEM. Excretory ducts are lined by small cup‐shaped basal cells and by tall cylindrical cells, which are completely covered by short processes oriented at random. When observed from below, after removal of the basal lamina, the basal surfaces of cells of excretory ducts exhibit polygonal areas delimited by short reliefs. Those of striated ducts show, instead, long laminar processes arranged radially.Results presented here are discussed and put in relationship to the mechanism of saliva production. © 1993 Wiley‐Liss, Inc.
Ultrastructural evidence for a binding substance to the sweet‐tasting protein thaumatin inside taste bud pores of rhesus monkey foliate papillae
Authors: Menco Bert Ph.M. , Hellekant Göran 
Published: February 2005

AbstractThaumatin is a protein that tastes intensely sweet only to Old World monkeys and to higher primates, including man. Here we used pre‐embedding ultrastructural methods to study the distribution of thaumatin in apical regions of Rhesus monkey foliate papillae, using thaumatin conjugated to 5 nm gold particles. With freeze‐substitution we saw that gold‐labeled thaumatin bound to an electron‐opaque, sponge‐like secretory substance inside the taste bud pores. Labeled thaumatin was found at the surface of the secretory substance even deep inside the pore, where other, unlabeled cellular structures surrounded the substance. With freeze‐fracture deep‐etching the secretory substance that bound the thaumatin‐gold particles appeared coarsely granular. There was no labeling of any other taste bud pore structure, including microvilli and small membranelined vesicles. Pre‐incubation with an excess of unlabeled thaumatin inhibited binding with goldlabeled thaumatin. The results suggest that the secretory substance had the greatest affinity of all taste pore structures to the sweet‐tasting compound under our experimental conditions. Therefore, gustatory reception probably involves various taste compound binding structures, microvilli, and also secretory substances like the one described here which bound thaumatin. We speculate that the secretory substance may bind taste stimuli and serve as an intermediate between stimuli and receptors. It could be involved in stimulus removal or delivery or both. © 1993 Wiley‐Liss, Inc.
HVEM ultrastructural analysis of mouse fungiform taste buds, cell types, and associated synapses
Authors: Kinnamon John C. , Henzler David M. , Royer Suzanne M. 
Published: February 2005

AbstractWe have used high voltage electron microscopy and computer‐generated three‐dimensional reconstructions from serial sections to elucidate the structure of taste bud cells and their associated synapses in fungiform taste buds of the mouse. Five fungiform taste buds (two of which were serially sectioned) were examined with the high‐voltage electron microscope (HVEM). We identified the synaptic connections from taste cells onto sensory nerve fibers and classified the presynaptic taste cells based on previously established ultrastructural criteria. From those data we have distinguished dark, intermediate, and light cells in murine fungiform taste buds. Synapses in murine fungiform taste buds are fewer in number, but contain many more vesicles than synapses in either foliate or circumvallate taste buds. Synapses in mouse circumvallate and foliate taste buds typically contain a few to several synaptic vesicles per section, whereas fungiform synapses may have in excess of 100 vesicles per profile. The significance of these differences in the numbers of synapses and synaptic structure between fungiform and circumvallate/foliate synapses is not known. Based on the small number of synapses observed in fungiform taste buds, we speculate that fungiform taste buds have only a few cells transducing sensory stimuli at any given time. Alternatively, communication of sensory information from the taste receptor cells to the afferent nerve fibers may be mediated by some other mechanism(s) in addition to classical chemical synapses. © Wiley‐Liss, Inc.
Sample preparation technique for cross‐sectional transmission electron microscopy of quantum wire structures
Authors: Chen Yu‐Pei , Reed Jason D. , O'Keefe Sean S. , Schaff William J. , Eastman Lester F. 
Published: February 2005

AbstractA novel cross‐sectional sample preparation technique for quantum wire (QWR) structures is described. By coating a thin layer of Au with a designed pattern on the sample as a marker to indicate the position of the wire pattern, the location of the thinned area can be controlled precisely. An example of applying this technique to an InGaAs/GaAs QWR structure is demonstrated. This technique can also be applied to any other small dimensional structures or devices with specific regions of interest. © Wiley‐Liss, Inc.
Selected area polishing for precision TEM sample preparation
Authors: Liu J. B. , Tracy B. M. , Gronsky R. 
Published: February 2005

AbstractA selected area mechanical polishing technique has been developed to improve the precision of cross‐sectional TEM sample preparation, based upon the early work of Benedict and colleagues [Benedict et al. (1990) MRS Symp. Proc. Vol. 199, p. 189]. TEM samples were made from a pre‐selected section through the middle of a 1 μm wide band of transistors extending laterally for more than 1 mm by precise control over the plane of polish with a corresponding reduction in sample preparation time. To illustrate the application of this technique, a uniformly thin, electron transparent TEM sample of a single, specific, failed transistor is obtained from a 4 mm by 10 mm device array. © Wiley‐Liss, Inc.
Transcellular and paracellular pathways in lingual epithelia and their influence in taste transduction
Authors: Simon Sidney A. , Holland Virgil F. , Benos Dale J. , Zampighi Guido A. 
Published: February 2005

AbstractThe lingual epithelium is innervated by special sensory (taste) and general sensory (trigeminal) nerves that transmit information about chemical stimuli introduced into the mouth to the higher brain centers. Understanding the cellular mechanisms involved in eliciting responses from these nerves requires a detailed understanding of the contributions of both the paracellular and transcellular pathways. In this paper we focus on the contribution of these 2 pathways to the responses of salts containing sodium and various organic anions in the presence and absence of amiloride. Electrophysiological recordings from trigeminal nerves, chorda tympani nerves, and isolated lingual epithelia were combined with morphological studies investigating the location (and permeability) of tight junctions, the localization of amiloride‐inhibitable channels, and Na‐K‐ATPase in taste and epithelial cells. Based on these measurements, we conclude that diffusion across tight junctions can modulate chorda tympani and trigeminal responses to sodiumcontaining salts and rationalize the enhancement of taste responses to saccharides by NaCl. © 1993 Wiley‐Liss, Inc.
Electron microscopic immunocytochemistry of glutamate‐containing nerve fibers in the taste bud of mudpuppy (Necturus maculosus)
Authors: Lu Kuo‐Shyan , Roper Stephen D. 
Published: February 2005

AbstractThe presence of glutamate immunoreactivity (glu‐IR) in the nerve fibers of the mudpuppy taste bud was investigated by electron microscopy. Pre‐embedding staining with avidinbiotin‐peroxidase complex (ABC) and post‐embedding staining with 5 mm colloid gold conjugates were used separately to identify immuno‐stained structures. We have found the following: 1) the majority of the nerve fibers innervating the mudpuppy taste bud are unmyelinated; 2) about 85% of nerve fibers located at the base of the taste bud and about 60% of the nerve fibers located between the taste cells show glu‐IR by pre‐embedding staining; 3) there is a preferential staining of the glu‐IR in the nerve fibers of the mudpuppy taste bud; and 4) the distribution of the colloidal gold particles in the nerve fibers is 1.5 to 2 times denser than that of the staining in the connective tissue background or cellular profiles of taste cells. From the distribution and pattern of the nerve fibers obtained in the thick and thin sections, we conclude that the mudpuppy taste bud is innervated by glutamate‐containing unmyelinated nerve fibers. © 1993 Wiley‐Liss, Inc.