bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toward an understanding of liposome structure through the use of computer graphic image correlation
Authors: Zasadzinski Joseph A. N. , Kerins John , Davis H. T. , Scriven L. E. 
Published: February 2005

AbstractA computer‐aided graphics approach to correlating transmission electron microscope images of freeze‐fractured and thin‐sectioned samples is outlined. Any three‐dimensional model of the imaged structure can be mathematically sectioned to provide a two‐dimensional representation of the model in the “fracture” plane. The method is used to demonstrate that the structure of lamellar liquid crystalline liposomes is based on a family of Dupin cyclides; closed, parallel surfaces with a conjugate ellipse and hyperbola as curvature defects.
Cytochemical identification of cerebral glycogen and glucose‐6‐phosphatase activity under normal and experimental conditions: I. Neurons and glia
Authors: Cataldo Anne M. , Broadwell Richard D. 
Published: February 2005

AbstractReliable ultrastructural techniques are applied for cytochemical identification of glycogen and localization of glucose‐6‐phosphatase (G6Pase) activity within neurons and glia of the adult mammalian CNS. Modulations in the cerebral localizations of glycogen and G6Pase activity are identified during various experimental conditions (i.e., salt‐stress, fasting, and trauma). The cytochemical reaction for demonstration of G6Pase activity implies that the enzyme acts as a phosphohydrolase to convert glucose‐6‐phosphate to glucose. The degradation of glycogen in vivo is one source of glucose‐6‐phosphate as a substrate for G6Pase. Glycogen is preserved by perfusion‐fixation of the brain with 2% glutaraldehyde‐2% formaldehyde. Chopper sections of this material are postfixed in buffered 1% osmium tetroxide‐1.5% potassium ferrocyanide, which serves as a contrast stain for glycogen, or in buffered 1% osmium tetroxide. Plastic‐embedded ultrathin sections of CNS tissue postfixed in 1% osmium tetroxide are stained for glycogen with periodic acid–thiocarbohydrazide‐silver protein. Intracellular glycogen appears as electron‐dense isodiametric particles and, under normal and experimental conditions, is most abundant within astrocytes. Neuronal glycogen is sparse to negligible normally but appears increased within specific neuronal populations during stressful states.Optimal preservation of G6Pase activity in the brain is obtained by brief perfusion‐fixation with 2% glutaraldehyde. Tissue sections are incubated in a modified Leskes medium containing glucose‐6‐phosphate or mannose‐6‐phosphate as substrate and lead nitrate. Utilizing the Gomori lead capture technique, G6Pase reaction product is localized within the lumen of the endoplasmic reticulum (ER) and related organelles (i.e., nuclear envelope, Golgi complex) of perikarya, dendrites, and glia. The ER in axons and axon terminals fails to express G6Pase activity under normal conditions but does so in some neurons exhibiting a degenerating appearance. A transient, cytochemical decrease in G6Pase activity may occur within some perikarya during stressed conditions.The results indicate that within neurons and glia of the adult CNS cytochemical stains are well suited for ultrastructural identification of glycogen and localization of G6Pase activity. Modulations in glycogen particle concentration and in localization of G6Pase activity in the neuron can occur in response to conditions that influence the energy metabolism of the cell. These modulations may reflect differences in the regional utilization of glucose as an energy‐producing substrate and as a derivative of glycogenolysis within the CNS.
Diffraction effect of x‐rays on the accuracy of quantitative analysis of crystals
Authors: Tanji Takayoshi , Yada Keiji , Kawamata Yasuhiro 
Published: February 2005

AbstractIn order to understand an apparent discrepancy of concentration of constituent elements in the quantitative analysis of thin KCl crystals with an energy dispersive X‐ray analyzer, which has been partly explained by fluorescent X‐ray excitation, more detailed experiments were carried out on binary alkali halides and tricomponent amorphous material by changing the azimuthal angle. Intensity ratios of X‐rays from the constituent elements in KCl and KBr single crystals varied considerably according to the rotation of the specimens. The observed differences between maximum and minimum intensity ratios were 15% for a thin KCl crystal about 100 nm thick and 20% for a bulk KCl crystal, which corresponded to 4.1% and 4.5% differences in atomic concentration, respectively. It was ascertained that for amorphous materials such as Co87Zr5Nb8, such a variation of the intensity ratio of X‐rays was not observed. It is thus proved that the variations of the intensity ratios of X‐rays from the constituent elements with azimuthal angle for KCl and KBr are attributed to the diffraction effect of characteristic X‐rays generated in crystalline specimens. This effect, which is the same as that in the production of Kossel patterns, is one of the essential factors limiting the accuracy of the analysis.
A staining syringe for multiple em grids
Authors: Järvilehto Matti , Harjula Riitta 
Published: February 2005

AbstractIn the EM‐routine, the thin sections are usually attached onto round copper grids. The sections on these EM‐grids are then stained either with a quite expensive automatic staining apparatus or by transporting the grids by hand from solution to solution. Here we will present a simple, inexpensive and truly reliable apparatus for staining and handling grids.
Comparison of polyethylene glycol and diethylene glycol distearate embedding methods for the preservation of fungal cytoskeletons
Authors: McKerracher Lisa J. , Heath I. Brent 
Published: February 2005

AbstractHyphae of the fungus Basidiobolus magnus were embedded in extractable polyethylene glycol (PEG) or diethylene glycol distearate (DGD) to prepare embedment‐free sections in order to seek components of the cytoskeleton that may be obscured in epoxy‐embedded sections. All methods showed that hyphae possess an intricate filamentous matrix, which is apparently unoriented. However, the appearance of the cytoskeleton depended on the embedding medium, the solvent used during embedding, and whether cells were fixed by conventional fixation or freeze‐substitution. PEG proved to be the best embedding medium for fungal cells because DGD caused cell shrinkage and produced a more lamellar than filamentous matrix. Also, the cytoskeletal filaments were clearer in freeze‐substituted cells than in conventionally‐fixed cells. Since we failed to find microtubules in the embedment‐free sections, we re‐embedded cells in Epon to discern whether microtubules or other cytoplasmic components had changed. Neither PEG nor DGD adequately preserved microtubules as compared to regular Epon‐embedded sections, and other cellular structures were significantly altered. Therefore, alternative methods need to be employed to further characterize fungal cytoskeletons.
Postembedding ultrastructural immunocytochemistry of neural antigens on tissues previously processed for routine light and electron microscopy: Preservation of antigenicity up to 22 years after initial fixation
Authors: Ross Amy A. 
Published: February 2005

AbstractA postembedding immunocytochemical technique is described that allows ultrastructural localization of glial fibrillary acidic protein and neuron‐specific enolase on tissues originally processed only for routine light and electron microscopy. Use of the oxidizing agent sodium metaperiodate prior to incubation with the primary antiserum sufficiently removes osmium tetroxide (OsO4) from potential antigen—antibody combining sites to allow specific localization of these neural antigens by colloidal gold immunolabelling. Both human and monkey neural tissues, prepared for routine ultrastructural examination with aldehyde fixatives and OsO4 postfixation, show excellent ultrastructural morphology and antigen localization. In addition, formalin‐fixed, paraffin‐embedded pathological human brain tissues, obtained at autopsy up to 22 years previously, show good ultrastructural immunolocalization of glial fibrillary acidic protein when re‐embedded for electron microscopy. Thus, ultrastructural immunolocalization of certain neural antigens is easily achieved in tissues originally processed for routine light and electron microscopy. This allows re‐examination of archival tissues using current immunocy‐tochemical advances, including that of selected pathological tissues previously prepared solely for light microscopy.
A vacuum system for the production of clean carbon films
Authors: Lamvik M. K. , Voreades D. , Norton P. , LeFurgey A. , Ingram P. 
Published: February 2005

AbstractA compact, oil‐free vacuum system has been assembled for the production of thin carbon films. Carbon rods are held in a simply constructed and easily cleaned rod holder. Using an unlubricated mechanical roughing pump and one sorption pump, the system is evacuated to the low millitorr range while completely avoiding oil vapors and contaminants that might derive from pump oil. Films produced in such systems are hydrophilic, and analytical electron microscopy measurements have shown that these films are adequately smooth and free of contaminants of both high and low atomic number.
An improved photographic process for convergent beam electron diffraction applications
Authors: Turner John H. , Krishnan Kannan M. 
Published: February 2005

AbstractThe use of a surface developer, pyrocatechol, to process transmission electron microscope negatives has been shown to have significant advantages over the conventional D‐19 process. The process described here is tolerant of a large margin of error in the electron exposure and produces a negative that not only retains details both in the highlight as well as the faint regions, but also preserves local contrast. These characteristics are particularly useful in convergent beam electron diffraction applications where one encounters a wide contrast range. Improved acuteness and an enhanced signal to noise ratio due to the prolonged exposures associated with this process have also been observed.
Preparation of holey carbon films suitable for cryo‐electron microscopy
Authors: Murray John M. , Ward Rob 
Published: February 2005

AbstractWe present a method for the quick and reliable production of carbon films perforated with 5–10‐μm holes, suitable for supporting suspensions that are to be rapidly frozen and imaged, using cryo‐electron microscopy, in the frozen‐hydrated state. The holes support biological specimens that are often embedded in 50–200 nm of vitreous ice, which is optimal for image contrast and preservation of large macromolecular complexes.
Use of backscattered electron imaging on developed radioautographic emulsions: Application to viewing rat incisor enamel maturation pattern following 45calcium injection
Authors: McKee M. D. , Warshawsky H. , Nanci A. 
Published: February 2005

AbstractBackscattered electron imaging (BEI) can be used to obtain compositional contrast in biological structures because it detects differences in concentration of elements with different atomic number. Rat incisor enamel shows a banded pattern in the maturation zone when radioautography is used to reveal the location of injected 45Ca at the enamel surface. The bands of developed silver grains in the photographic emulsion that coats the enamel surface are ideal for atomic number contrast. The purpose of this study was to use BEI to analyze the radioautographic pattern with SEM resolution. One‐month‐old rats were injected with 45Ca and sacrificed at early (1 min, 5 min, 30 min), intermediate (4 h, 8 h), and late (1 day, 4 days) time intervals after injection. Whole incisors were dissected, the enamel organs were removed, and the enamel surface was coated with photographic emulsion and processed for radioautography. These radioautographed teeth were examined with a JEOL JSM‐840 SEM equipped with a JEOL backscatter annular‐type detector. At the early time intervals, light microscopic examination showed five or six broad black bands running obliquely across the teeth. These were separated by narrow white bands of unlabeled enamel. BEI resolved the presence of a delicate subbanding pattern within each dark band. At the intermediate time intervals, although the incisal bands persisted, only a diffusely blackened apical area was seen by light microscopy. BEI resolved bands in this apical region, but these showed no subbanding pattern. At the late time intervals, both light microscopy and BEI showed no banding, and the enamel was uniformly labeled. The significantly improved resolution obtained with BEI on surface radioautographs has revealed a previously undetected substructure in the 45Ca‐labeled banding pattern seen in enamel maturation.
Three‐dimensional analysis of high voltage electron microscope tilt images: Methods and problems
Authors: Hama Kiyoshi , Arii Tatsuo 
Published: February 2005

AbstractA quantification program for obtaining three‐dimensional image information from high voltage electron microscope stereo pair pictures was developed for a Luzex 5000 image analyzer. A zero tilt image was used as a reference. A real‐time image processor system was introduced to improve the image quality and to reduce the beam damage of the specimens. Some modifications of the optical system and the specimen stage were made to improve the accuracy and efficiency of stereoscopy. The accuracy of the measurement was considerably improved by these modifications. Some basic problems and limitations of the method are discussed.
Rapid Embedding in Lowicryl K4M for Immunoelectron Microscopic Studies
Authors: Simon Gerard T. , Thomas Jennifer A. , Chorneyko Kathy A. , Carlemalm Eric 
Published: February 2005

AbstractA rapid method of embedding tissues in Lowicryl K4M was developed. The initiator was replaced with benzoin ethyl ether, and the temperature of polymerization under indirect ultraviolet light was increased from −35°C to −10°C. The complete polymerization occurred in 24 hours. Compared with the original method and two other rapid methods proposed by Altman et al. (J. Histochem. Cytochem. 32:1217–1223, 1984), the above mentioned rapid method gave more reproducible results, and the preservation of the tissues was better. The preservation of the antigenicity was excellent as tested with anti‐amylase on zymogen granules of the rat's exocrine pancreas and with anti‐zona pellucida on ova of the golden hamster. Comparison of the preservation of antigenicity by means of the new rapid method shows an increased specific labeling when using the rapid Lowicryl K4M method as compared to the original Lowicryl K4M and Epon. Background levels between the original and rapid Lowicryl K4M methods are not significantly different. However, the two Lowicryl K4M methods differ significantly when compared to Epon. The reliability of this rapid method makes it suitable for introduction not only for research but also as a routine diagnostic histochemical technique at the ultrastructural level.
A glow discharge unit to render electron microscope grids and other surfaces hydrophilic
Authors: Aebi Ueli , Pollard Thomas D. 
Published: February 2005

AbstractWe describe the design, construction, and operation of a simple glow discharge unit that can be used to make surfaces such as carbon‐coated electron microscopy grids and glass coverslips hydrophilic. The use of a vacuum leak detector (Tesla coil) in place of a conventional high‐voltage power supply and a small plastic desiccator for the vacuum chamber make the unit very inexpensive. Owing to the small volume of the chamber and the simplicity of the unit, the whole glow discharge process can be carried out in only 2 to 3 min, a time considerably shorter than that required for conventional vacuum evaporators. The hydrophilic surface improves adsorption of particles by several orders of magnitude in preparation for negative staining, freeze‐drying, and other procedures.
Application of two‐bath development processing to transmission electron films and plates
Authors: Morse Daniel F. 
Published: February 2005

AbstractIn particular areas of materials research transmission electron microscopy has traditionally been plagued by the seemingly inherent problems of excessive photographic contrast and high densities. This need not always be the case. This article will suggest that the use of a development process in which the developing agent and its accelerator are split into two baths can accomplish the desirable effects of compressing the contrast range of the negative and limiting excessive density without loss of recorded detail. The developer used in the study is a commercially available formula called Diafine. Two‐bath developers can be formulated by individuals. At the time of writing, Diafine was the only off‐the‐shelf split developer known to the author.
Quantitative ultrastructural approach to the study of the spatial relationships among cell organelles. I. Cytological organization of human exocrine epithelia
Authors: Diaz Giacomo , Cossu Margherita , Riva Alessandro 
Published: February 2005

AbstractCurrently available morphometric methods provide useful information on the three‐dimensional properties (such as volume, surface, etc.) of biological structures. These methods, however, do not reveal how the same structures are spatially organized within the cell. A sum of problems, which concern mainly the definition of shape and location of the sectioned structures, does not allow the three‐dimensional representation of the organelle arrangement from a quantitative analysis of sections. Following a different approach, this study considers the topographic relationship between ten distinct subcellular structures: nucleus, Golgi, ribosomes, mitochondria, lysosomes, lipid droplets, secretory granules, and apical, lateral, and basal plasmalemma. The analysis of associations from 2 × 2 tables calculated for each pair of structures and the pattern of multiple associations obtained by clustering methods provide a useful description of the spatial relationship among different cell compartments. The results of the investigation carried out in parallel on seven human exocrine glands (pancreas, parotid gland, submandibular gland, lacrimal gland, ceruminous gland, ampulla of the vas deferens, and seminal vesicle) allow an immediate evaluation of the method and a comparative analysis of the cytologic organization of secreting cells of human exocrine glands.
A microcomputer program for the generation of random grid squares in quantitative analysis
Authors: Webber James S. 
Published: February 2005

AbstractSubjectivity in selecting random grid squares for routine quantitative analysis can be circumvented through a combination of finder grids and a computer program. The simple BASIC program described in this paper generates a list of random grid‐square numbers, which are sequentially analyzed. The concept was applied in the quantitation of asbestos and other microparticles in environmental samples. The use of finder grids and this program can also be useful in quality‐control programs and in cross‐referencing analyses, as well as in the study of biological specimens.
Cross‐sectional transmission electron microscopy of silicon LSI circuits and josephson junction devices
Authors: Du A. Y. , Chu Y. M. 
Published: February 2005

AbstractCross‐sectional transmission electron microscopy (XTEM) has been used to diagnose silicon LSI circuits and Josephson junction devices. For LSI circuits, some typical failure problems have been presented. For Nb‐Si‐Nb Josephson junction, microholes in the thin silicon layer have observed, and they are responsible for the short circuiting of these devices.
Theoretical research on electron optics
Authors: Ximen Jiye 
Published: February 2005

AbstractThis paper summarizes theoretical research on electron optics in the field of electron microscopy that has been carried out by the author and his colleagues over a long period of time. The main topics to be discussed include the rotationally symmetrical imaging system and its aberrations; the method of matrix algebraic calculation and its applications to electron optics; new developments in scanning electron beam systems, i.e., the combined elec‐tromagnetic focusing‐deflection system with superimposed fields; the electromagnetic multipole system and its aberrations; the ion optical system with a curvilinear axis and its aberrations; and the phase retrieval in Fourier electron microscopy. This review may help to promote a better understanding of the present state of, and trends in, Chinese electron optics research.
Estimation of the mean caliper: A new simple approach
Authors: Elmalek Michelle , Hammel Ilan 
Published: February 2005

AbstractMorphometric measurements are commonly carried out on structures the shape of which approximates that of a sphere. We calculated some stereological data of eosinophil granules by using digitized planimetry, performed on transmission electronmicrographs. By using a new approach for mean caliper (D) estimation and extrapolating an approximate granule axial ratio, we were able to calculate the granule density size. We deduced from a numerical analysis for various sphere sizes distributions from which an underestimation of not more than 4% may be contributed to D in most cases, assuming that the diameter coefficient of variation is less than 35%. The methodology we propose for mean ellipsoid caliper estimation seems to be useful in cases in which the disector method is not suitable.
EELS log‐ratio technique for specimen‐thickness measurement in the TEM
Authors: Malis T. , Cheng S. C. , Egerton R. F. 
Published: February 2005

AbstractWe discuss measurement of the local thickness t of a transmission microscope specimen from the log‐ratio formula t = λ In (It/I0) where It and I0 are the total and zero‐loss areas under the electron‐energy loss spectrum. We have measured the total inelastic mean free path λ in 11 materials of varying atomic number Z and have parameterized the results in the form λ = 106F (E0/Em)/ln (2βE0/Em) where F = (1 + E0/1,022)/(1 + E0/511)2, the incident energy E0 is in keV, the spectrum collection semiangle β is in mrad, and Em = 7.6Z0.36. This formulation should allow absolute thickness to be determined to an accuracy of ±20% in most inorganic specimens.
Technique for preparing cross‐section transmission electron microscopy specimens from ceramic oxide braze joints
Authors: Santella Michael L. , Fisher Alex T. , Haltom C. Paul 
Published: February 2005

AbstractA method for preparing cross‐section transmission electron microscopy specimens from alumina and partially stabilized zirconia braze joints is described. The technique relies on masking a mechanically dimpled 3mm disc in order to avoid preferential thinning of the metallic braze filler alloy during ion milling. The results presented show that specimens made by this technique are suitable for characterizing the fine microstructural details of interfacial reactions at oxide surfaces that occur during brazing.