Journal articles: 'Electron microscopy specimens preparation'

1

Stadtländer, Christian T. K. H. "Dehydration and Rehydration Issues in Biological Tissue Processing for Electron Microscopy." Microscopy Today 13, no. 1 (January 2005): 32–35. http://dx.doi.org/10.1017/s1551929500050847.

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Electron microscopy (EM) is an indispensable tool for the study of ultrastructures of biological specimens. Every electron microscopist would like to process biological specimens for either scanning electron microscopy (SEM) or transmission electron microscopy (TEM) in a way that the specimens viewed under the electron microscope resemble those seen in vivo or in vitro under the light microscope. This is, however, often easier said than done because biological tissue processing for EM requires careful attention of the investigator with regard to the numerous processing steps involved in specimen preparation, such as fixation, dehydration, infiltration, embedding, and sectioning.

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Robinson, Vivian. "A Review Of The Development Of Scanning Electron Microscopy At High Chamber Pressure." Microscopy Today 5, no. 1 (January 1997): 14–15. http://dx.doi.org/10.1017/s1551929500059964.

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Ever since electron microscopes were developed, it has been the goal of microscopists to observe specimens in their natural state, free from artefacts which can often be introduced through specimen preparation. For most biological specimens, that includes the presence of water. With a pressure of 10-4 torr or lower required to operate a scanning electron microscope (SEM), liquid water, which required a pressure of above 5 torr, was clearly a problem.Although several attempts had been made to examine hydrated specimens in a SEM, the first published results of water imaged in a stable and reproducible manner in the SEM, were presented at the Eighth International Congress on Electron Microscopy in Canberra in 1974 (Robinson, 1974).

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Liu, Dang-Rong, H. E. George Rommal, and David B. Williams. "Preparation of lithium specimens for transmission electron microscopy." Journal of Electron Microscopy Technique 4, no. 4 (1986): 381–83. http://dx.doi.org/10.1002/jemt.1060040408.

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Cieslinski, R. C., M. T. Dineen, J. G. Marshall, J. H. Blackson, D. Mizer, and H. L. Garrett. "Artifacts of preparation in polymer microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 700–701. http://dx.doi.org/10.1017/s0424820100155475.

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The interpretation of, and information available from a transmission electron photomicrograph, frequently depend upon specimen preparation. A major consideration in the selection of a preparation method is the potential for preparation artifacts. The goal of this work is to illustrate some sectioning and staining artifacts found in the preparation of a variety of polymer specimens. The following artifacts, in addition to several others, will be presented during the poster session.

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Melanson, Linda. "A Versatile and Affordable Plunge Freezing Instrument for Preparing Frozen Hydrated Specimens for Cryo Transmission Electron Microscopy (CryoEM)." Microscopy Today 17, no. 2 (March 2009): 14–17. http://dx.doi.org/10.1017/s1551929500054432.

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CryoEM is a powerful tool in the arsenal of structural biologists and soft polymer chemists. Hydrated specimens require a preservation method that will counteract the effects of the electron beam and the high vacuum environment of the electron microscope. Classical specimen preparation techniques using chemical fixatives are not able to capture the native structure of the once hydrated specimen perfectly. In contrast to classical methods for preserving specimens for electron microscopy, rapid freezing of radiation-sensitive specimens such as dispersed biological macromolecular assemblies, 2D crystals, and colloids allows the structural details of the specimen to be captured in their essentially native state to near atomic resolution.

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Wolff, T. "Preparation of Drosophila Eye Specimens for Scanning Electron Microscopy." Cold Spring Harbor Protocols 2011, no. 11 (November 1, 2011): pdb.prot066506. http://dx.doi.org/10.1101/pdb.prot066506.

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Wolff, T. "Preparation of Drosophila Eye Specimens for Transmission Electron Microscopy." Cold Spring Harbor Protocols 2011, no. 11 (November 1, 2011): pdb.prot066514. http://dx.doi.org/10.1101/pdb.prot066514.

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Stupina, T. A. "Preparation of Articular Cartilage Specimens for Scanning Electron Microscopy." Bulletin of Experimental Biology and Medicine 161, no. 4 (August 2016): 558–60. http://dx.doi.org/10.1007/s10517-016-3460-9.

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9

Martone, Maryann E., Andrea Thor, Stephen J. Young, and Mark H. Ellisman. "Correlated 3D Light and Electron Microscopy of Large, Complex Structures: Analysis of Transverse Tubules in Heart Failure." Microscopy and Microanalysis 4, S2 (July 1998): 440–41. http://dx.doi.org/10.1017/s1431927600022327.

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Light microscopic imaging has experienced a renaissance in the past decade or so, as new techniques for high resolution 3D light microscopy have become readily available. Light microscopic (LM) analysis of cellular details is desirable in many cases because of the flexibility of staining protocols, the ease of specimen preparation and the relatively large sample size that can be obtained compared to electron microscopic (EM) analysis. Despite these advantages, many light microscopic investigations require additional analysis at the electron microscopic level to resolve fine structural features.High voltage electron microscopy allows the use of relatively thick sections compared to conventional EM and provides the basis for excellent new methods to bridge the gap between microanatomical details revealed by LM and EM methods. When combined with electron tomography, investigators can derive accurate 3D data from these thicker specimens. Through the use of correlated light and electron microscopy, 3D reconstructions of large cellular or subcellular structures can be obtained with the confocal microscope,

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OZERLER, MUSTAFA. "On the Specimen Preparation Techniques for Examining Geological Specimens Using Scanning Electron Microscopy." Journal of King Abdulaziz University-Earth Sciences 3, no. 1 (1990): 369–75. http://dx.doi.org/10.4197/ear.3-1.32.

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Dorling, M., and J. Zussman. "An investigation of nephrite jade by electron microscopy." Mineralogical Magazine 49, no. 350 (March 1985): 31–36. http://dx.doi.org/10.1180/minmag.1985.049.350.04.

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AbstractTwo specimens of tremolite and one of richterite, all with nephrite jade texture, have been examined by transmission electron microscopy using ion-thinning for specimen preparation. The specimens contain clusters of very small lath-like crystallites with z-axes approximately parallel but in a range of azimuthal orientations. It is suggested that these clusters which are themselves in varied orientations are the result of post-tectonic recrystallization of strained amphibole crystals, the new crystals inheriting the z-axis orientations of the old. The extreme toughness of nephrite jade is attributed to a number of the sub-microscopic features observed, including the sizes, habits, and orientations of its crystallites, and the nature of its grain boundaries.

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Apkarian, Robert P. "Comments on Cryo High Resolution Scanning Electron Microscopy." Microscopy Today 12, no. 1 (January 2004): 45. http://dx.doi.org/10.1017/s1551929500051841.

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Stephen Carmichael wrote about Cryoelectron Tomography in the May 2003 issue of Microscopy Today. Citing new preparation methods, small cells can be vitrified, observed frozen in the TEM and a series of digital images captured while the specimen is being rotated around the axis perpendicular to the electron beam producing a 3-D tomogram. Gina Sosinski and Maryann Martone wrote about imaging big and messy biological structures using cryo-electron Tomography in the July issue of Microscopy Today. Cryo-HRSEM now also seeks to provide 3-D information approaching the molecular level from frozen hydrated cell and molecular systems. Vitrification procedures for small specimens such as platelets and biomolecules on grids are accomplished by plunge freezing in liquefied etiiane as is done with cryo-TEM procedures. Bulk specimens such as organic hydrogels and tissues are routinely high pressure frozen (HPF) in 3mm gold planchets. Employing an in-lens cryostage, identical to those used in cryo-TEM, cryo-HRSEM provides 3-D high-resolution images because secondary electrons are efficiently collected above the lens in a single scan thus minimizing specimen irradiation.

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Vijayan, Sriram, Joerg R. Jinschek, Stephan Kujawa, Jens Greiser, and Mark Aindow. "Focused Ion Beam Preparation of Specimens for Micro-Electro-Mechanical System-based Transmission Electron Microscopy Heating Experiments." Microscopy and Microanalysis 23, no. 4 (June 5, 2017): 708–16. http://dx.doi.org/10.1017/s1431927617000605.

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AbstractMicro-electro-mechanical systems (MEMS)-based heating holders offer exceptional control of temperature and heating/cooling rates for transmission electron microscopy experiments. The use of such devices is relatively straightforward for nano-particulate samples, but the preparation of specimens from bulk samples by focused ion beam (FIB) milling presents significant challenges. These include: poor mechanical integrity and site selectivity of the specimen, ion beam damage to the specimen and/or MEMS device during thinning, and difficulties in transferring the specimen onto the MEMS device. Here, we describe a novel FIB protocol for the preparation and transfer of specimens from bulk samples, which involves a specimen geometry that provides mechanical support to the electron-transparent region, while maximizing the area of that region and the contact area with the heater plate on the MEMS chip. The method utilizes an inclined stage block that minimizes exposure of the chip to the ion beam during milling. This block also allows for accurate and gentle placement of the FIB-cut specimen onto the chip by using simultaneous electron and ion beam imaging during transfer. Preliminary data from Si and Ag on Si samples are presented to demonstrate the quality of the specimens that can be obtained and their stability during in situ heating experiments.

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Fortunati, K., M. Fendorf, M. Powers, C. P. Burmester, and R. Gronsky. "Preparation of BiCaSrCuO specimens for High-Resolution Transmission Electron Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 714–15. http://dx.doi.org/10.1017/s0424820100155542.

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Transmission electron microscopy, in particular high-resolution TEM, is proving to be a valuable tool in the continuing effort to characterize and understand the “high-Tc” superconducting oxides. Since specimen quality is of critical importance in high-resolution studies, care must be taken to choose the most appropriate specimen preparation technique for the material under study. The BiCaSrCuO material investigated here was in the form of small, sintered pellets with a porous microstructure which consists of small, randomly oriented, poorly connected, plate-like grains (see Figure 1). We have found that this morphology can significantly effect the production of suitable TEM specimens.The simplest and most rapid specimen preparation method employed consists of crushing a small amount of the starting material to a fine powder in an agate mortar and suspending the powder in pure ethanol or propanol. An eye dropper or syringe is then used to transfer 4-6 drops of the suspension onto a holey carbon film supported on a mesh grid, thus effectively dispersing the powder across the grid. A strong tendency for the crystal to cleave along (001) planes, due to the weak bonding between BiO layers, results in flake-like particles which exhibit a preferred [001] orientation on the grid. A high-resolution image of a specimen prepared using this method is shown in Figure 2. We have observed that some specimens produced in this manner are unstable under a 200kV beam (with LaB6 filament), with heavy damage occurring within the time that a through-focus series of micrographs can be exposed. It is also important to note that since separation along grain boundaries occurs during crushing, this method is not an appropriate choice for imaging grain boundary structures.

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Ishizuka, Kazuo, Paul H. C. Eilers, and Toshihiro Kogure. "Optimal Noise Filters in High-Resolution Electron Microscopy." Microscopy Today 15, no. 5 (September 2007): 16–21. http://dx.doi.org/10.1017/s1551929500061186.

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Most of the specimens for high-resolution electron microscopy have amorphous surface layers due to contamination during observation and/or damaged surface layers during specimen preparation. Moreover, many specimens are radiation sensitive, and a part of the specimen easily becomes amorphous during the observation. These amorphous materials make clear observation of crystal structure difficult. A periodic structure may be extracted by simply using a periodic mask in Fourier space. However, this kind of mask often introduces a periodic feature in addition to the crystal structure. To reduce such artifacts a Wiener filter or an average background subtraction filter has been discussed. However, these filters do not work for non-ideal crystals, such as cylindrical crystals and nano-crystals, where a translational periodicity is limited to the order of nano-meter. In this report we improve these filters by introducing new ways to estimate a contribution from the amorphous materials.

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McDonald, K. L., D. J. Sharp, and W. Rickoll. "Preparation of Drosophila Specimens for Examination by Transmission Electron Microscopy." Cold Spring Harbor Protocols 2012, no. 10 (October 1, 2012): pdb.top068452. http://dx.doi.org/10.1101/pdb.top068452.

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17

Cabanillas, E. D., and R. Versaci. "Preparation of narrow amorphous ribbon specimens for transmission electron microscopy." Ultramicroscopy 26, no. 3 (January 1988): 335–36. http://dx.doi.org/10.1016/0304-3991(88)90233-1.

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18

Goodhew, Peter J. "Preparation of plan view and cross-sectional specimens for TEM." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 706–7. http://dx.doi.org/10.1017/s0424820100149362.

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The preparation of thin specimens remains one of the most important aspects of electron microscopy. Over the forty years in which materials TEM has been practised the rate of introduction of radically new techniques has been very low. In the 1960s microscopists were using electropolishing, chemical polishing, mechanical polishing, ion beam thinning and ultramicrotomy, many of which are also covered in this symposium thirty years later. The last three decades have seen a process of refinement and automation so that success rates and areas of thin sample are both much higher in the 1990s than they were in the 1960s. However the preparation of good specimens still requires skill and an element of "art" remains. The increase in electron energy which helped microscopists to overcome limitations of specimen preparation in the 1970s has now (for very good reasons) stopped, so the basic specimen thickness requirements for standard microscopy are now stable.

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Tanaka, Keiichi. "High-resolution scanning electron microscopy in biology." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 3 (August 12, 1990): 14–15. http://dx.doi.org/10.1017/s0424820100157607.

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With the development of scanning electron microscope (SEM) with ultrahigh resolution, SEM became to play an important role in not only cytology but also molecular biology. However, the preparation methods observing tiny specimens with such high resolution SEM are not yet established.Although SEM specimens are usually coated with metals for getting electrical conductivity, it is desirable to avoid the metal coating for high resolution SEM, because the coating seriously affects resolution at this level, unless special coating techniques are used. For avoiding charging effect without metal coating, we previously reported a method in which polished carbon plates were used as substrate. In the case almost all incident electrons penetrate through the specimens and do not accumulate in them, when the specimens are smaller than 10nm. By this technique some biological macromolecules including ribosomes, ferritin, immunoglobulin G were clearly observed.Unfortunately some other molecules such as apoferritin, thyroglobulin and immunoglobulin M were difficult to be observed only by the method, because they had very low contrast and were easily damaged by electron beam.

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Müller, M., and R. Hermann. "High-Resolution Scanning Electron Microscopy of Biological Specimens." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 186–87. http://dx.doi.org/10.1017/s0424820100103012.

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Three major factors must be concomitantly assessed in order to extract relevant structural information from the surface of biological material at high resolution (2-3nm).Procedures based on chemical fixation and dehydration in graded solvent series seem inappropriate when aiming for TEM-like resolution. Cells inevitably shrink up to 30-70% of their initial volume during gehydration; important surface components e.g. glycoproteins may be lost. These problems may be circumvented by preparation techniques based on cryofixation. Freezedrying and freeze-substitution followed by critical point drying yields improved structural preservation in TEM. An appropriate preservation of dimensional integrity may be achieved by freeze-drying at - 85° C. The sample shrinks and may partially collapse as it is warmed to room temperature for subsequent SEM study. Observations at low temperatures are therefore a necessary prerequisite for high fidelity SEM. Compromises however have been unavoidable up until now. Aldehyde prefixation is frequently needed prior to freeze drying, rendering the sample resistant to treatment with distilled water.

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Zhang, W., L. Theil Kuhn, P. S. Jørgensen, K. Thydén, J. J. Bentzen, E. Abdellahi, B. R. Sudireddy, M. Chen, and J. R. Bowen. "Transmission Electron Microscopy Specimen Preparation Method for Multiphase Porous Functional Ceramics." Microscopy and Microanalysis 19, no. 2 (February 13, 2013): 501–5. http://dx.doi.org/10.1017/s1431927613000019.

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AbstractAn optimum method is proposed to prepare thin foil transmission electron microscopy (TEM) lamellae of multiphase porous functional ceramics: prefilling the pore space of these materials with an epoxy resin prior to focused ion beam milling. Several advantages of epoxy impregnation are demonstrated by successful preparation of TEM specimens that maintain the structural integrity of the entire lamella. Feasibility of the TEM alignment procedure is demonstrated, and ideal TEM analyses are illustrated on solid oxide fuel cell and solid oxide electrolysis cell materials. Some potential drawbacks of the TEM specimen preparation method are listed for other samples.

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Shannon, C. Urbanik, L. A. Giannuzzi, and E. M. Raz. "Microstructural Characterization of Automated Specimen Preparation for TEM Analysis." Microscopy and Microanalysis 6, S2 (August 2000): 528–29. http://dx.doi.org/10.1017/s1431927600035133.

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Automated specimen preparation for transmission electron microscopy has the obvious advantage of saving personnel time. While some people may perform labor intensive specimen preparation techniques quickly, automated specimen preparation performed in a timely and reproducible fashion can significantly improve the throughput of specimens in an industrial laboratory. The advent of focused ion beam workstations for the preparation of electron transparent membranes has revolutionized TEM specimen preparation. The FIB lift-out technique is a powerful specimen preparation method. However, there are instances where the “traditional” FIB method of specimen preparation may be more suitable. The traditional FIB method requires that specimens must be prepared so that the area of interest is as thin as possible (preferably less than 50 μm) prior to FIB milling. Automating the initial specimen preparation for brittle materials (e.g., Si wafers) may be performed using the combination of cleaving and sawing techniques as described below.

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Lacroix, Christian R., and Judith MacIntyre. "New techniques and applications for epi-illumination light microscopy." Canadian Journal of Botany 73, no. 11 (November 1, 1995): 1842–47. http://dx.doi.org/10.1139/b95-196.

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This modification to the technique of epi-illumination light microscopy makes use of a new system of lenses that replaces expensive and not readily available dipping cone objectives. The newer objectives offer at least comparable resolution and depth of field, along with simple preparation procedures. An epi-illumination system is a good intermediate between the stereo microscope and a scanning electron microscope, offering magnification at high power that can aid in evaluation of potential scanning electron microscope specimens, as well as the time- and material-saving feature of being able to eliminate unsuitable scanning electron microscope specimens. Key words: technique, epi-illumination, morphogenesis, vegetative apex, primordium, staining.

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Brickey, M. R., and J. L. Lee. "New Technique for Successful Thermal Barrier Coating Specimen Preparation for Transmission Electron Microscopy." Microscopy and Microanalysis 6, no. 3 (May 2000): 231–36. http://dx.doi.org/10.1017/s1431927600000386.

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AbstractReliability of thermal barrier coatings (TBC) hinges on the adhesion of a thermally grown oxide scale to an insulative ceramic topcoat and an underlying metallic bondcoat. The width of the scale and its interfaces makes transmission electron microscopy (TEM) an appropriate tool for its analysis. However, specimen preparation has proven to be a challenging obstacle leading to a dearth of TEM research on TBCs. A new approach to cross-section TBC TEM specimen preparation is described. The principal advantages of this technique are reproducibility, reduced specimen damage, and time savings resulting from decreased ion milling. This technique has been successfully applied to numerous TBC specimens with various thermal histories.

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Brickey, M. R., and J. L. Lee. "New Technique for Successful Thermal Barrier Coating Specimen Preparation for Transmission Electron Microscopy." Microscopy and Microanalysis 6, no. 3 (May 2000): 231–36. http://dx.doi.org/10.1007/s100059910024.

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Abstract Reliability of thermal barrier coatings (TBC) hinges on the adhesion of a thermally grown oxide scale to an insulative ceramic topcoat and an underlying metallic bondcoat. The width of the scale and its interfaces makes transmission electron microscopy (TEM) an appropriate tool for its analysis. However, specimen preparation has proven to be a challenging obstacle leading to a dearth of TEM research on TBCs. A new approach to cross-section TBC TEM specimen preparation is described. The principal advantages of this technique are reproducibility, reduced specimen damage, and time savings resulting from decreased ion milling. This technique has been successfully applied to numerous TBC specimens with various thermal histories.

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KOMOTO, Tadashi. "Preparation of Specimens for Electron Microscopy and Its Application to Polymers." Kobunshi 47, no. 8 (1998): 538–41. http://dx.doi.org/10.1295/kobunshi.47.538.

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Peters, Klaus-Ruediger. "In environmental Scanning Electron Microscopy, the secondary electron signal reveals surface information not accessible by conventional backscattered electron signals." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 78–79. http://dx.doi.org/10.1017/s0424820100152367.

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Environmental scanning electron microscopes (ESEM) operate at high as well as at low vacuum (<2.5 kPa: ~20 Torr) but utilize all advantages of conventional high vacuum SEM (large specimen size, high depth of focus and specimen tilt capability, TV-rate scanning for imaging dynamic events). They have the advantage of imaging wet specimens as well as insulators without the need of any specimen preparation. Previously, environmental scanning microscopy was restricted to the BSE signal collected with BSE detectors. SE signals cannot be collected with the Everhart-Thornley detector because it cannot operate at low vacuum. Using positively biased electron collectors, it is now possible to collect an SE signal. However, the origin and quality of this signal need to be further characterized.An ElectroScan ESEM was used equipped with SE and BSE detectors and operated at 7-30 kV with partial water pressures of 0.1-2.5 kPa (∼1-20 Torr).

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McDowall, A. W., J. M. Smith, and J. Dubochet. "Thin sectioning for cryo transmission electron microscopy (cryo TEM)." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 102–3. http://dx.doi.org/10.1017/s0424820100142153.

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Processing whole cells and tissues for conventional TEM is known to cause structural alterations. Much effort has been devoted, therefore, to developing techniques which avoid specimen preparation artefacts. Recently, research using a cryo-electron microscope has shown that biological suspensions embedded in vitreous ice retain their structural integrity, and when compared with conventionally prepared TEM specimens, are free from many of the classical artefacts. In order to extend the advantage of cryo TEM to whole cells and tissues, we have developed a method of thin sectioning vitrified material.

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Ellis, E. Ann, and Michael W. Pendleton. "Vapor Coating: A Simple, Economical Procedure for Preparing Difficult Specimens for Scanning Electron Microscopy." Microscopy Today 15, no. 3 (May 2007): 44–45. http://dx.doi.org/10.1017/s1551929500055553.

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The Microscopy and Imaging Center at Texas A&M University is a multi-user facility involved with preparation and analysis of many different biological and materials sciences projects. Vapor stabilization and coating is an important part of our specimen preparation methodology for difficult biological and materials, especially polymer, samples. The procedure for all our vapor preparation techniques is done in a simple, economical apparatus set up in a properly functioning fume hood with a flow rate of at least 100 ft/min (Fig. 1). The apparatus is made from a glass petri dish or a glass petri dish for the bottom and an appropriate size beaker for the top. Specimens, mounted on stubs, are placed inside the chamber and the fixative (osmium tetroxide, ruthenium tetroxide or acrolein) is placed in a small container (plastic bottle cap) near the specimens.

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Mai, Hartmut. "A new method for SEM analysis of both proximal and distal sides of the same coccolith." Journal of Paleontology 62, no. 01 (January 1988): 151–52. http://dx.doi.org/10.1017/s0022336000059047.

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Disperse coccoliths and whole coccospheres are external calcareous skeletal fragments or skeletons produced by unicellular marine and lacustral algae which belong to the Chrysomonadales. Their diameters vary between 2 and 13 microns, which means electron microscopy is the most appropriate method to study their form and ultrastructure. In most cases, coccoliths have two distinct sides, a proximal side toward the cellular body of the living organism and a distal side facing the surrounding water (Figure 1). Normally these two sides differ strongly from each other and therefore paleontologists are frequently confronted with the difficulty of relating both sides of the same object when classifying a specimen. A preparation method introduced by Perch-Nielsen (1967) showed some possibilities for observing the same nannofossil specimens by light microscope and transmission electron microscope, whereas Thierstein et al. (1971) and Moshkowitz (1974) explained methods which allow scanning electron and light microscopy of the same coccoliths. Mai (1983) showed how to prepare a sample for light, scanning electron, and transmission electron microscopy in order to study the same coccoliths. Until now no method has been developed for using SEM to study the proximal and distal sides of the same specimen. Publication of a preparation method for SEM observations may solve this problem and be useful for paleontologists investigating calcareous nannoplankton.

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More, K. L., D. W. Coffey, and T. S. Geer. "Preparation of fragile catalyst materials for TEM." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 412–13. http://dx.doi.org/10.1017/s0424820100138439.

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A novel specimen preparation technique for transmission electron microscopy (TEM) has been developed which allows for the preservation of constituent placement within a variety of diesel and automotive catalyst materials. The standard preparation method for imaging catalyst particles and washcoat constituents has been to use powders scraped from the substrate surface. However, while limited imaging of fine scale structures is possible on clean specimens using this method, all cross-sectional spatial information is lost. Thus, scraped powder specimens cannot be used to directly image surface effects in the TEM or to view large areas of "intact" material in these catalyst systems. Also, for many microscopy investigations such as electron energy loss spectroscopy and high resolution imaging, powders can be too thick. Other preparation techniques have also been used, for example ultramicrotomy and model systems, with some limited success. It is clear that by preparing TEM specimens using this cross-section technique, changes in microstructure to either precious metal particles or washcoat constituents with distance from the exposed surface can be evaluated as a function of aging, engine use, or process modification.

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Klomparens, Karen L. "Ultrathin sectioning and staining artifacts in transmission electron microscopy specimen preparation." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 340–41. http://dx.doi.org/10.1017/s0424820100086003.

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Ultrathin sectioning followed by staining of sections are the final two steps in the preparation procedure for transmission electron microscope (TEM) specimens. While each requires an understanding of the scientific principles involved, these steps, perhaps more than any others, also require meticulous attention to detail and, for ultrathin sectioning, considerable skill and practice. Even with a properly fixed and infiltrated specimen in a well-polymerized block, there are a number of factors which can contribute to artifacts in ultrathin sections. Most can be corrected or at least minimized assuming that the ultramicrotome environment is well-situated; i.e., free of vibration, excessive heat, humidity, and air currents.

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Allard, L. F., K. S. Ailey, A. K. Datye, and W. C. Bigelow. "An Ex-SituReactor with Anaerobic Specimen Transfer Capabilities for TEM Studies of Reactive (Catalyst) Specimens." Microscopy and Microanalysis 3, S2 (August 1997): 595–96. http://dx.doi.org/10.1017/s1431927600009867.

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The optimization of currently available catalysts and the development of new ones requires a detailed understanding of the effects of both microstructure and composition on their function. Previous work has demonstrated that information at the atomic-scale on heterogeneous catalysts can be derived using high resolution transmission electron microscopy (TEM). Under favorable conditions, the morphology of heavy metal catalytic particles can be related to catalytic activity. It has been shown that preoxidation can disrupt the surface of small metal particles causing altered activity and selectivity in reactions such as alkane hydrogenolysis. Metals such as Pt, Rh, or Ru are noble and pick up no more than a monolayer of oxygen when exposed to air during sample preparation for microscopy. This oxygen monolayer is not imaged in the microscope, most likely because the oxygen desorbs during exposure to the high energy electron beam. However, when metals such as Fe, Co, Ni, Pd or Cu are exposed to air, there is a corrosive interaction that alters particle structure quite dramatically.

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Skepper, Jeremy N. "Biological specimen preparation for transmission electron microscopy." BioEssays 21, no. 9 (August 25, 1999): 802. http://dx.doi.org/10.1002/(sici)1521-1878(199909)21:9<802::aid-bies12>3.0.co;2-z.

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Roomans, G. "Biological Specimen Preparation for Transmission Electron Microscopy." Cell Biology International 23, no. 8 (August 1999): 592. http://dx.doi.org/10.1006/cbir.1999.0409.

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Shaapur, F. "Ion thinning of integrated circuit transverse specimens for transmission electron microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1426–27. http://dx.doi.org/10.1017/s0424820100131760.

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Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.

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Sweet, Walter C. "Scanning electron microscopy and photomicrography." Paleontological Society Special Publications 4 (1989): 351–55. http://dx.doi.org/10.1017/s2475262200005347.

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In the last two decades, scanning electron miocroscopy has come to be the technique of choice in studies of microfossil structure and morphology. Scanning electron microscope (SEM) photomicrographs are easy to produce, have great depth of field, and resolve minute details over a wide range of magnifications. Hence photomicrographs of images produced in a SEM are now more widely used than ordinary photographs in the illustration of microfossils. Techniques for preparation, mounting and manipulation of specimens in the SEM vary with the instrument available, aims of the study, and skill of the operator. Hence attention is directed here primarily to general aspects of SEM technique.

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Cruz-Reyes, J., M. Avalos-Borja, M. H. Farias, and S. Fuentes. "Electron Microscopy in hydrodesulfurization catalysts." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 260–61. http://dx.doi.org/10.1017/s0424820100174436.

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Applications of transition metal sulfides for hydroprocessing catalysts have included a variety of reactions. It is generally believed that an interaction between the active phase (Mo or W) and the promoter (Co or Ni) takes place. Several models have been suggested to explain the enhanced catalytic activity. The catalytic properties of the unsupported sulfides are dependent on the catalyst preparation methods . In this work we study by electron microscopy two sets of unsupported samples ranging from molybdenum sulfide to cobalt sulfide. The specimens were prepared by the following methods, a slight variation of the classical homogeneous sulfide precipitation (HSP) method, and a new method called impregnated thiosalt decomposition (ITD).

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Stevie, F. A., C. B. Vartuli, R. H. Mills, R. B. Irwin, T. L. Shofner, and L. A. Giannuzzi. "The FIB Lift-Out Specimen Preparation Technique for TEM Analyses and Beyond: SEM, AUGER, STEM, and SIMS Applications." Microscopy and Microanalysis 5, S2 (August 1999): 888–89. http://dx.doi.org/10.1017/s1431927600017761.

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The use of focused ion beams (FIB) to prepare site specific specimens for transmission electron microscopy (TEM) and scanning electron microscopy (SEM) has been well documented. The 5 to 7 nm resolution on the latest FIB instruments has enhanced the ability to locate and expose features of interest. The use of the lift-out technique of FIB specimen preparation removes the need for prior thinning of the sample for TEM analysis and permits the study of materials that were difficult or impossible to do previously. Use of high current (10 nA) FIB instruments makes specimen preparation possible in less than one hour; automatic operation of FIB instruments will further reduce this time. After milling in the FIB, specimens are micromanipulated in air onto a 3 mm diameter TEM sample grid coated with carbon. The ability to analyze lift-out specimens using other analytical techniques that can take advantage of this site specific capability was previously suggested.

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Tang, Kai. "Correlation of micromagnetic structure and microstructure in thin film longitudinal magnetic recording media." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 108–9. http://dx.doi.org/10.1017/s042482010013691x.

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Lorentz transmission electron microscopy (LTEM) has long been used as a tool for imaging the magnetic domain structure in materials and has occasionally been applied to thin film longitudinal magnetic recording media. Conventional/high-resolution electron microscopy (TEM) has shown its power in revealing the detailed microstructure of these materials. The combination of these two techniques can result in a more complete understanding of the interdependence of micromagnetic structure and microstructure and provide insight into how to improve the magnetic performance.LTEM requires specimens with large uniformly thin areas so that the deflection angle of the incident electron beam is proportional to the magnetic field within the specimen plane. Conventional specimen preparation methods, which normally generate a wedge, are therefore no longer suitable. Previous work has used specially designed substrates to facilitate preparation of LTEM specimens of Co alloy/Cr magnetic media. In the present study a chemical etching technique was introduced to successfully produce LTEM specimens directly from the C/Co alloy/Cr/NiP/Al(substrate) structures, typical of those currently used in the magnetic disk industry.

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Chestnut, H., D. P. Siegel, J. L. Burns, and Y. Talmon. "A temperature-jump technique for time-resolved cryo-transmission Electron Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 742–43. http://dx.doi.org/10.1017/s0424820100155682.

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Transmission electron microscopy of rapidly-frozen, hydrated specimens (cryo-TEM) is a powerful way of examining labile microstructures. This technique avoids some artifacts associated with conventional preparative methods. Use of a controlled environment vitrification system (CEVS) for specimen preparation reduces the risk of unwanted sample changes due to evaporation, and permits the examination of specimens vitrified from a defined temperature. Studies of dynamic processes with time resolution on the order of seconds, in which the process was initiated by changes in sample pH, have been conducted. We now report the development of an optical method for increasing specimen temperature immediately before vitrification. Using our method, processes that are regulated by temperature can be initiated in less than 500 msec on the specimen grid. The ensuing events can then be captured by plunge-freezing within an additional 200 msec.Dimyristoylphosphatidylcholine (DMPC) liposomes, produced by extrusion, were used as test specimens. DMPC undergoes a gel/liquid crystalline transition at 24°C, inducing a change in liposome morphology from polyhedral to spherical. Five-μl aliquots of DMPC dispersions were placed on holey-carbon-filmed copper grids mounted in the CEVS environmental chamber, and maintained at 6-8°C and 80% relative humidity. Immediately before the temperature jump most of the sample was blotted away with filter paper, leaving a thin specimen film on the grid. Upon pressing the trigger, an electronic control circuit generated this timed sequence of events. First, a solenoid-activated shutter was opened to heat the specimen by exposing it for a variable time to the focused beam of a 75W Xenon arc lamp. Simultaneously, a solenoid-activated cryogen shutter in the bottom of the CEVS was opened. Next, the lamp shutter was closed after the desired heating interval. Finally, a solenoid-activated cable release was used to trigger a spring-loaded plunger in the CEVS, propelling the sample into a reservoir of liquid ethane. Vitrified samples were subsequently transferred to a Zeiss EM902 TEM, operated in zero-loss brightfield mode, for examination at −163°C.

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Suzuki, T., M. Kudo, Y. Sakai, and T. Ichinokawa. "Material Contrast of Scanning Electron and Ion Microscope Images of Metals." Microscopy Today 16, no. 1 (January 2008): 6–11. http://dx.doi.org/10.1017/s1551929500054250.

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The rapid technical development of FIM (Focused Ion Beam) technology has spawned an increase in spatial resolution capability in scanning ion microscopy (SIM) technology. Furthermore, FIM has been used for preparation of thin specimens in transmission electron microscopy and micro-fabrication of electronic devices in the semiconductor industry. Recently, a scanning ion microscope with a helium field ion source has been developed. Thus, the contrast formation of emission electron images in scanning ion microscopy has been the object of study for analyzing images of materials specimens, similar to the theory behind scanning electron microscope (SEM) contrast formation. Furthermore, whether the electron emission yield γ induced by ion impact is periodic or non-periodic as a function of Z2 (the atomic number of the target) has not been well studied in the low energy region from several keV to the several tens of keV values used in SIM.

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Anderson, Ron. "Tutorial: Tem Specimen Preparation in the Physical Sciencestripod Polishing and Ion Milling." Microscopy and Microanalysis 4, S2 (July 1998): 876–77. http://dx.doi.org/10.1017/s1431927600024508.

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Over the past few decades, the demands of modern analytical electron microscopy have increased the need for TEM specimen preparation techniques with a minimum of misleading artifacts in terms of chemical microanalysis. At the same time, the demands of modern industrial materials, be they semiconductor, polymeric or composite in nature, call for speed, flexibility and high spatial resolution as well. The response from the electron microscopy community, especially that portion in the private sector, have been to devise (or advocate) radically different forms of TEM thin specimen preparation from that of classic replication, electropolishing and ion thinning.This tutorial sets forth the goals of TEM specimen preparation, and the requirements for a "good" TEM specimen. The strategic choices governing which technique to use for preparing a wide variety of specimens will be covered. A TEM Specimen Preparation Flow Chart will be used to plot a course that makes optimum use of the preparation techniques available as a function of the type of specimen to be prepared.

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Wergin, William P., Richard M. Sayre, and Terrence W. Reilly. "Low-voltage field-emission scanning electron microscopy applications in nematology." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 420–21. http://dx.doi.org/10.1017/s0424820100104169.

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Conventional scanning electron microscopy (CSEM) has long been used to gain structural information on the taxonomy, morphology, host-parasite relationships and predators of plant parasitic nematodes. Although a significant amount of new information has accumulated during the past few years, further gains in structural detail will be hampered because CSEMs have resolutions of 40-70A, 5-20kV accelerating voltages are normally required to excite adequate secondary electrons, and current preparation techniques require specimen coatings of 200-300A.Recently a new SEM, the Hitachi S900, combined a condensor-objective lens system with a field emission electron source. This instrument, known as a field emission (FE) SEM, has a resolution of about 5A or 10 times greater than that of CSEMs, can be used to observe specimens with little or no coating and operates at accelerating voltages as low as 1 or 2 kV while producing electron densities nearly 1000 times brighter than those of CSEMs.

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Probst, Wolfgang, Erhard Zellmann, and Richard Bauer. "Energy-Filtered Electron Microscopy (EFEM) of Frozen Hydrated Biological Specimens." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 274–75. http://dx.doi.org/10.1017/s0424820100180124.

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The preparation of hydrated biological specimens for the use in a TEM has made a great stride foreward due to the work of Dubochet et al. on vitrification and Muller et al. on high pressure freezing. Transfer units and cryo stages for the microscopes allow imaging of specimens in the 100K range. Due to simple physical reasons, however, contrast of such kinds of specimen is still a problemm in conventional transmission electron microscopes (CTEM). Solutions as they are provided by an EFEM will be shown and explained in the following.Ice is the main constituent of frozen hydrated specimens. The large ratio of inelastic-to-elastic total cross section of 4.0 in case of ice which is even more than that for carbon results in an unavoidable high amount of inelastically scattered electrons. Blurred images and lacking contrast are due to that fact. The EEL spectra from a frozen hydrated section of biological material before and after freeze drying in the microscope document this fact. (Figure 1). Increased scattering probability and thickness contribute to the inelastic loss. In Figure 2 the EEL spectrum from a thin pure ice layer without any support is compared to the spectrum from thin freeze dried cryo section on a thin support. In case of ice the maximum of the low loss range is clearly shifted towards zero loss, mainly due to oxygen low loss and plasmon and to hydrogen core loss. Thus for the images shown in the following Figures a narrow energy window of 10 eV is used really to cut off all the inelastically scattered electrons.

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Dube, Prakash, Holger Stark, Elena V. Orlova, Michael Schatz, Erich Beckmann, Friedrich Zemlin, and Marin van Heel. "3-D structure of single macromolecules at 15Å resolution by cryo-microscopy and angular reconstitution." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 838–39. http://dx.doi.org/10.1017/s0424820100140567.

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Electron cryo-microscopy of individual non-crystallized macromolecules (“single particles”) is a very rapid technique for probing the three-dimensional (“3D”) structure of biological macromolecules. By exploiting the different orientations of the macromolecules in the embedding medium, one may extract 3D information from the data without ever collecting tilt series in the microscope. The angular reconstitution approach, designed for this purpose, was recently extended with a number of refinements which allow its use as a routine technique for finding 3D structures of macromolecules with arbitrary pointgroup symmetry, from entirely asymmetric ribosomes to viruses with icosahedral symmetry.The specimen preparation technique associated with the angular reconstitution approach is simple and fast since crystallization experiments are avoided altogether. The vitreous-ice embedding specimen preparation technique remains one of our favorite specimen preparation techniques. We are, however, currently experimenting with specimens embedded in glucose and ammonium molybdate or other heavy-metal salts. Collecting good micrographs can also be quite straightforward since the images are taken from untilted specimens, while exposing each image area only once.

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Yamada, M., K. Ueda, K. Kuboki, H. Matsushima, and S. Joens. "Scanning electron microscopy of plant cells using a variable-pressure SEM and cryogenic techniques." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 260–61. http://dx.doi.org/10.1017/s0424820100147144.

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Use of variable Pressure SEMs is spreading among electron microscopists The variable Pressure SEM does not necessarily require specimen Preparation such as fixation, dehydration, coating, etc which have been required for conventional scanning electron microscopy. The variable Pressure SEM allows operating Pressure of 1˜270 Pa in specimen chamber It does not allow microscopy of water-containing specimens under a saturated vapor Pressure of water. Therefore, it may cause shrink or deformation of water-containing soft specimens such as plant cells due to evaporation of water. A solution to this Problem is to lower the specimen temperature and maintain saturated vapor Pressures of water at low as shown in Fig. 1 On this technique, there is a Published report of experiment to have sufficient signal to noise ratio for scondary electron imaging at a relatively long working distance using an environmental SEM. We report here a new low temperature microscopy of soft Plant cells using a variable Pressure SEM (Hitachi S-225ON).

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Fisher, A. T., and P. Angelini. "Preparation of Backthinned Ceramic Specimens." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 182–83. http://dx.doi.org/10.1017/s0424820100117881.

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Analytical electron microscopy (AEM) of the near surface microstructure of ion implanted ceramics can provide much information about these materials. Backthinning of specimens results in relatively large thin areas for analysis of precipitates, voids, dislocations, depth profiles of implanted species and other features. One of the most critical stages in the backthinning process is the ion milling procedure. Material sputtered during ion milling can redeposit on the back surface thereby contaminating the specimen with impurities such as Fe, Cr, Ni, Mo, Si, etc. These impurities may originate from the specimen, specimen platform and clamping plates, vacuum system, and other components. The contamination may take the form of discrete particles or continuous films [Fig. 1] and compromises many of the compositional and microstructural analyses. A method is being developed to protect the implanted surface by coating it with NaCl prior to backthinning. Impurities which deposit on the continuous NaCl film during ion milling are removed by immersing the specimen in water and floating the contaminants from the specimen as the salt dissolves.

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BARRÉ, CÉLINE, DAVID O'NEIL, and V. MONICA BRICELJ. "PREPARATION OF LARGE BIVALVE SPECIMENS FOR SCANNING ELECTRON MICROSCOPY USING HEXAMETHYLDISILAZANE (HMDS)." Journal of Shellfish Research 25, no. 2 (August 2006): 639–41. http://dx.doi.org/10.2983/0730-8000(2006)25[639:polbsf]2.0.co;2.

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Noguchi, K., M. Araki, and Y. Ohno. "The preparation of transmission electron microscopy specimens of as-drawn gold wire." Scripta Materialia 43, no. 3 (July 2000): 199–204. http://dx.doi.org/10.1016/s1359-6462(00)00391-2.

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Journal articles on the topic 'Electron microscopy specimens preparation'

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