bluuebunny/crossref_metadata_2025_split huggingface dataset:
A technique for controlling the placement of the thin area in electrojetpolished tem foils of tungsten
Authors: Fekete J. R. , Gibala R. 
Published: February 2005

AbstractRecently we have been making extensive use of TEM observations of grain boundaries in a research program concerned with the deformation behavior of tungsten bicrystals. A major problem in this research involved the preparation of thin foils which contained the grain boundary in the electron tranparent region, since standard cell type electrojetpolishing techniques do not allow adequate control of the placement of the thin area. Since the grain boundary comprises a very small percentage of a foil, good thin area placement control is critical to obtaining useful samples consistently. Masking techniques which use electrically insulating lacquers are not precise enough to guarantee the position of the thin area. However, we have found that one can use the dishing characteristic of the jetpolisher (i.e., the fact that the center of the foil thins faster than the perimeter) in conjunction with the masking technique to predict the position of the thin area within a preferentially thinned region created by the masking procedure outlined below. This is the essence of the procedure outlined below.
Protein casting: A new replication technique for observing fluid surface structures
Authors: Garber M. A. , McManus W. , Bennett B. , Hunter R. L. 
Published: February 2005

AbstractCertain insoluble copolymers form characteristic liquid crystalline structures at water/copolymer interfaces. The formation of these structures, discernable with phase contrast microscopy, correlates with biological activities as immunological adjuvants. In order to study such structures at the electron microscopic level, it was necessary to develop a preparation technique which preserved the water/polymer interface. A technique was devised, here called “protein casting,” which uses highly concentrated bovine serum albumin (BSA) in water, subsequently fixed with glutaraldehyde, to form a replica of the water/polymer interface. These casts appeared highly accurate at low magnifications, and resolved to less than 1ønm. This technique seems ideal for accurate replication of surfaces formed by nonmiscible liquids and should prove helpful in studies of other materials in aqueous suspension.
An image processing method for scanning electron microscopy based on the information transmission theory
Authors: Kanaya Koichi , Oho Eisaku , Naka Michiaki , Koyanagi Takehiko , Sasaki Toshihide 
Published: February 2005

AbstractBased on the information transmission theory, topographic image signals in scanning electron microscopy are used to evaluate contrast, gradient, acutance, and Laplacian operator, the total of which represent the image sharpness of an edge line.One may consider the impulse and step functions as an input to the Gaussian system function of a low‐pass filter, the impulse and step response functions possibly representing a single spot and image contrast of an edge profile, respectively. It is shown that the response function of acutance defined as the power of the gradient normalized by density is a more realistic representation of image edge sharpness. Also, edge sharpness can be greatly enhanced by utilizing the Laplacian operator through digital image processing for a disk specimen model with a rounded edge.Contrast increased by specimen tilt, and an edge effect due to side‐scattered electrons, as well as the signal attenuation by specimen collection, are consistently obtained as the response function in the system.The exact measurement of spot size and edge‐to‐edge resolution, and image sharpness improvement, are derived by digital image processing.
Aldehyde fixatives: Quantification of acid‐producing reactions
Authors: Johnson Timothy J. A. 
Published: February 2005

AbstractUnder conditions commonly used for the preservation of tissue for electron microscopy, substantial amounts of hydrogen ions were produced when either formaldehyde or glutaraldehyde was added to solutions of amines or proteins, or to tissue homogenates. In glycine‐aldehyde reactions, hydrogen ions were generated in linear proportion to the glycine concentration over the range of 0.001 M to 0.100 M glycine. In the presence of 1% formaldehyde or 1% glutaraldehyde, 0.3–0.9 equivalents of acid were produced per mole of primary amine. This variation is a function of the specific primary amine used. Acid production increased with increasing formaldehyde concentration but did not increase appreciably with increasing glutaraldehyde concentration. The concentration of amines in tissue is high. These amines are probably responsible for much of the acid generated when aldehydes react with tissue homogenates. In amine‐aldehyde reactions, the positive charge originally associated with the parent amine is simultaneously neutralized with the formation of hydrogen ions. Thus, in tissues exposed to aldehydes, there is a decrease in the overall positive charge which is related to the amount of acid generated. The inherent buffering capacity of liver and muscle was not sufficient to prevent large pH decreases when aldehydes were added to homogenates of these tissues. These data suggest that significant but transient pH decreases may occur within cells exposed to aldehydes. To minimize the aldehyde‐induced pH decreases, a buffer should be chosen so that its pKa is 0.2–0.3 pH units less than the pH desired for a particular experiment. In addition, buffer concentrations of at least 0.10 M are suggested for fixatives in order to provide adequate buffering capacity during tissue preservation.
Motorization of the dupont‐sorvall mt‐1 ultramicrotome
Authors: Caceci Thomas 
Published: February 2005

AbstractA Dupont‐Sorvall MT‐1 ultramicrotome, normally a manually operated instrument, was equipped with a small motor. Ultrathin sections were successfully cut at rates from one to five sections per minute. This lowcost conversion to automatic operation offers an alternative to the purchase of a new ultramicrotome, as well as making a classic instrument more flexible.
Direct determination of ultrathin section thickness using latex particles
Authors: Jésior Jean‐Claude 
Published: February 2005

AbstractA method is proposed to determine ultrathin section thickness by means of noncentral sections obtained from latex spheres. The resulting spherical segments provide the parameters necessary to calculate very simply the section thickness without further treatment. The method is illustrated by an example using the grid‐sectioning technique and could be generalized to classical microtomy.
Tracing axons in the human brain: A method utilizing light and TEM techniques
Authors: Sadun Alfredo A. , Schaechter Judith D. 
Published: February 2005

AbstractThe neuroanatomy of experimental animals has been investigated through a variety of histological and physiological techniques. Recently, more sophisticated methods have permitted a better understanding of the complex connections of animal brains. In contrast, the methods available for the direct examination of the human brain have remained relatively primitive.We have developed a staining method (paraphenylene‐diamine method: PPD) which bridges the techniques of light and electron microscopy. The method permits the tracing of degenerated fibers in the human brain even after very long survival periods. With this method we have documented several visual pathways not previously described in man. We have also demonstrated, in several species, that products of axonal degeneration remain far longer than previously supposed. The PPD technique is relatively simple, reliable, provides high resolution, works in human brains, and can be used in conjunction with TEM.
Complementary freeze fracture replication: An example of its use in the study of horizontal cell gap junctions of the carp retina
Authors: Tonosaki Akira , Washioka Hiroshi , Nakamura Hidenori , Negishi Koroku 
Published: February 2005

AbstractDark‐adapted carp retinas were fixed with glutaraldehyde, frozen in liquid nitrogen slush, and their complementary replicas were harvested using a bipolar‐vacuum evaporater. On montage pictures, plasmic (PFF) and ectoplasmic fracture faces (EFF) of the external horizontal cells (EHC) were marked, and PFF of gap junction (GJ) areas were scrutinized by virtue of particulate aggregation visible at relatively low magnification. Summation of digitized values obtained from a complementary pair of replicas was taken to represent all existent GJ areas in an examined EHC surface. A similar method was applied to large horizontal processes (LHP) that are located in the inner‐most part of the internal nuclear layer and currently accepted to be extensions of EHC. The occurrence of fractured faces of plasma membrane was smaller in EHC than LHP. The percentage of GJ areas was about ten times larger in EHC than LHP. Examining complementary replicas at relatively low magnification appears to be useful for facilitating quantitative analysis of intercellular coupling by GJ structures.
A method of direct particle deposition on a carbon planchet to study mineral dust in human lung by scanning electron microscopy
Authors: Kimizuka Goro , Wang Nai‐San 
Published: February 2005

AbstractFollowing Na‐hypochlorite digestion of lung tissue, mineral particles extracted in the chloroform layer were deposited directly on a pre‐smoothed carbon planchet for combined scanning electron microscopy and X‐ray energy dispersive spectrometry (SEM and XEDS). Total mineral particle counts were obtained, and detailed physical characteristics of the fibrous particles were documented at 600, 1,500, 4,500 and 9,000 x in three lungs without, and one lung with, histories of occupational exposure. This preparation method was simple, collected more than 99% of identifiable mineral particles in the chloroform layer, gave excellent object to background contrast without heavy metal coatings, and was suitable for XEDS. Comparable fibrous particles from the chloroform layer could also be studied by selected‐area electron diffraction to complement the results of XEDS. By this method, we found particles or fibers larger than 0.1 μm were readily counted and measured at 4,500 x. At 600 x, ferruginous bodies were found to be more than twice in number than when sought for by light microscopy. It was determined that 4,500 x is the most efficient magnification to examine and diagnose this type of specimen. The present study illustrates the importance of determining the most efficient magnification to be utilized in particle counts.
Preparation of fish tissues for electron microscopy
Authors: Olson Kenneth R. 
Published: February 2005

AbstractMany of the techniques applied to study the morphology of lower vertebrates were originally developed for analysis of mammalian tissues. However, not all of these methods, especially those involving tissue perfusion, can be directly applied to piscine tissues because of the considerable physiological differences between fish and mammals. The present paper examines these physiological variables in fish and describes how they might affect morphological studies that employ tissue perfusion. A method for perfusion of fish tissues is described in detail. This procedure can be used for administration of fixatives, chemical markers, and vascular replicating resins.
A deposition technique for the imaging and analysis of protein interactions with metal and semiconductor surfaces
Authors: Panitz J. A. , Andrews C. L. , Bear D. G. 
Published: February 2005

AbstractA new technique for placing biological molecules on metal, insulator, and semiconductor surfaces is described. The procedure requires only 10 μl of solution containing molecules at a concentration of 0.1—10 μg/ml. The use of a buffer that does not affect metal substrates, the possibility of fixing the molecules in solution prior to deposition, and the ability to minimize surface tension forces during air drying are other features of the new protocol. Simultaneous deposition on TEM grids and highly curved substrates permits biomolecular adsorption on technologically interesting materials to be visualized in the transmission electron microscope.
A method for abolishing the nonspecific binding artifacts produced by the peroxidase‐antiperoxidase complex (PAP) in immunostained mucous epithelia
Authors: Sowinski Janice M. , Mackay Robert L. , Nicosia Santo V. 
Published: February 2005

AbstractThe presence of nonspecific staining artifacts is a potential problem in ultrastructural immunocytochemistry. In the course of staining for lysozyme in the human and rabbit endocervix, the peroxidase‐antiperoxidase complex (PAP) was found to bind to mucous granules in a selective and nonspecific manner. Sections etched in 10% aqueous H2O2, incubated for 5 minutes in 1:50 PAP in Tris‐buffered saline (TBS) and subsequently treated with 3, 3′‐diaminobenzidine‐H2O2, revealed a staining precipitate within the matrix of mucous granules. The same selective and nonspecific staining could also be visualized when horseradish peroxidase (1 mg/ml) was substituted for PAP in the immunocytochemical sequence. Thus, this staining method made the reliable demonstration of the desired antigen difficult. The affinity of PAP for mucous granules can be completely eliminated by subjecting sections, previously etched in H2O2 to expose the antigenic sites, to a 3‐minute incubation in immunoglobulin (1:10 human IgA, 1:5 human IgG, or 1:5 antihuman IgG) immediately prior to using PAP in the standard immunocytochemical staining sequence. The use of this modification to Sternberger's unlabeled antibody‐enzyme method is recommended because it allows for the elimination of all nonspecific staining artifacts without interfering with specific localization by the primary antibody. The mechanism that causes nonspecific binding of peroxidase to mucous granule constituents is unclear, although carbohydrate binding may play a role in the interaction between mucous granules and peroxidase.
The use of histograms for transmission electron microscopy: Defocus and astigmatism correction at high resolution
Authors: Krakow William 
Published: February 2005

AbstractA real‐time method for optimizing the defocus of a conventional transmission electron microscope in the phase contrast imaging mode has been investigated using image histogram data. This method can also be used to minimize the objective lens astigmatism. It will be shown both theoretically and empirically, using a digital television frame store, that a histogram will give the largest peak when an image has a broad and flat contrast transfer function. This method has distinct advantages of speed and minimal computational requirements over obtaining the power spectrum of an image.
Real time uses of color for electron microscopy via a television‐rate digital frame store
Authors: Krakow William 
Published: February 2005

AbstractAn on‐line television‐rate digital frame store device is utilized to provide color representations of a wide range of electron microscope images and image data. Various types of hardware devices in the frame store coupled with software manipulations via the host computer make rapid image acquisition, modification, measurement, and full‐color display possible in real time either from micrographs or directly from an electron microscope. Lookup tables used in conjunction with grey‐level image memories can be controlled from a menu display to provide a wide range of color‐coding schemes and sequencing. It is also possible to use color graphics overlays and alpha numeric displays along with full‐color image displays. This paper will describe many of the recent applications of color developed for electron microscopy studies of materials.
Layered crystal thin films
Authors: Hines R. L. , Patterson C. E. 
Published: February 2005

AbstractA rigid peripheral clamp with an annular heater is used to bond layered crystals to grids with a thermoplastic adhesive. The layered crystals are subsequently cleaved with adhesive tape while bonded to the grid. The final layered crystal thin film covering a grid opening is exposed only to room air and is free from adhesive or fluid contamination. The results of preparation of several layered crystals, including muscovite mica, molybdenite, and talc, are described.
A method for preparing powdered specimens for transmission electron microscopy
Authors: Carr Martin J. 
Published: February 2005

AbstractA new method of preparing TEM samples from powders is described. The method consists of compacting epoxy‐powder composite mixtures in special molds by centrifuging prior to polymerization. The compact is then ion milled by standard methods. Samples prepared in this way are currently being used to study dislocation structures developed during processing of ceramic powders.
Silver impregnation applied to striated muscle: The sarcoplasmic reticulum
Authors: Scales Donald J. , Yasumura Thomas 
Published: February 2005

AbstractThe classical black reaction developed by Camillo Golgi is shown to impregnate the tubules and fenestrations of the sarcoplasmic reticulum (SR) in striated muscle. This is a double impregnation of chromate and silver, which usually fills extracellular spaces. The method is difficult insofar as long incubation times are required, and location of the successfully “stained” SR in plastic‐embedded tissue blocks is unpredictable. The light microscope is absolutely necessary to find the good regions which can then be cut from the blocks in 1‐μm‐thick sections and examined in the electron microscope. Stereo pairs give the best results since these resolve overlap problems common to thick sections. A variety of artifacts are illustrated which can help avoid erroneous interpretations. The Golgi‐“stained” SR shows this elusive network with unsurpassed contrast and should benefit the morphological studies of muscle‐membrane enthusiasts.
Scanning electron microscopic observations on deembedded biological tissue sections: Comparison of different fixatives and embedding materials
Authors: Russell Scott D. , Daghlian Charles P. 
Published: February 2005

AbstractConventional plant histological specimens fixed in formalin‐acetic acid‐alcohol, chromic acid‐acetic acid‐formaldehyde, or glutaraldehyde‐osmium and embedded in either paraffin or plastic are examined as possible rapid methods for providing an alternative image of cellular structure by using scanning electron microscopy. Using the mitotic figures of actively growing onion root tips as a study specimen, the organization of the nucleus and spindle apparatus is reasonably well preserved as compared with isolated mitotic spindles and studies of mitosis in endosperm tissue. Relief of internal structure in this technique is obtained through the coagulant nature of the fixative. Used judiciously, this technique can reveal aspects of the three‐dimensional nature of internal tissue structure that may otherwise be difficult to discern.
The preparation of ultrathin frozen sections for immunocytochemistry at the electron microscope level
Authors: Christensen A. Kent , Komorowski Thomas E. 
Published: February 2005

AbstractA description of ultrathin frozen sectioning is presented. Small pieces of lightly‐fixed but unembedded tissue are cryoprotected in 80% sucrose, mounted on chucks and frozen in liquid nitrogen. Frozen sections approximately 100 nm thick for electron microscopy are cut at about −90°C, using a cryosectioning unit mounted on a conventional ultramicrotome. Sections are picked up from the surface of the knife with a droplet of 80% sucrose, and are applied to membrane‐coated EM grids at room temperature. The mounted sections are then used for EM immunocytochemistry. Essentially the same sectioning procedure can provide frozen sections 1 μm thick for light microscope immunocytochemistry.
Some characteristics of epoxy embedding resins and how they affect contrast, cell organelle size, and block shrinkage
Authors: Mollenhauer Hilton H. , Droleskey Robert E. 
Published: February 2005

AbstractThe effects of epoxy resin formulation on tissue contrast and organelle size were evaluated by examining thin sections of rat liver in the electron microscope and by doing a simple morphometric analysis of peroxisome and nuclear size. Contrast was greatest for tissues embedded in the Quetol formulation of Kushida and least for tissues embedded in the Ladd formulation. Epon 812, Epon‐Araldite, and Spurr formulations gave results intermediate to those of the Quetol and Ladd formulations. Organelle size was greatest for tissues embedded in the Ladd formulation and smallest for tissues embedded in the Spurr formulation. The maximum size differences were approximately 15%. Epon 812, Epon‐Araldite, and Quetol formulations gave results (for organelle size) intermediate to those of the Ladd and Spurr formulations. The gross shrinkage properties of the epoxy resin blocks were all the same and, therefore, could not account for the differences in organelle size.
A procedure to prepare cross‐sectional samples for TEM
Authors: Rivaud Lydia 
Published: February 2005

AbstractCross‐sectional transmission electron microscopy (XTEM) is an imaging technique particularly suited to the study of layered structures. For integrated electronic devices it has become a common practice to use XTEM to assess the shape and crystallinity of component layers as well as defect structures introduced by processing. A procedure for preparing samples to be viewed by XTEM is described.
Identification of bacteria by studying one section under light microscopy, scanning, and transmission electron microscopy
Authors: Saglie F. R. , Sa Ferreira J. C. , Smith C. T. , Valentin P. L. , Carranza F. A. , Newman M. G. 
Published: February 2005

AbstractA method for bacterial identification has been developed by means of studying the same histological sections through several types of microscopy. With this method, one section was processed and analyzed respectively for light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Sections of gingival biopsies were Gram stained and bacteria tentatively identified by LM. Photographs of the sections were taken and presketched transparent acetate sheets (PTAS) were made from the photos. The same section was later prepared for SEM, areas previously thought to contain bacteria were localized by placing the PTAS onto the SEM monitoring screen. The SEM specimens were subsequently processed for TEM, bacteria were located, and micrographs obtained. The results showed that out of ten diseased gingival biopsies observed under the LM, bacteria were found to be present in all the specimens and were identified as both Gram positive and Gram negative. By transferring the section from LM to SEM, the bacteria could be relocated and their morphotype (cocci, rods, etc.) clearly identified in most of the cases. Since cocci may resemble other biological granular structures under SEM, they require further analysis under TEM for additional positive identification. This study demonstrated that the method described here is a useful tool for assessing the presence and identifying bacteria within the gingival tissues.
Electron beam radiation damage to organic inclusions in ice as an analytical tool for polymer science
Authors: Talmon Yeshayahu , Narkis Moshe , Silverstein Michael 
Published: February 2005

AbstractA method is proposed to enhance contrast between microdomains of two‐component polymer systems using electron beam radiation damage. The technique is based on the different damage patterns to crosslinking‐type and scission‐type polymer particles embedded in ice. Whereas the former lose little mass and cavities form in the ice around them, the latter lose much more mass, become cellular in appearance, and occasionally swell. Applications of the technique are demonstrated by revealing the microstructure of two‐stage poly(butylacrylate)/polystyrene latices, their size distributions, and the presence of single‐component particles in the two‐component system.