bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of holz pattern shifts in convergent beam diffraction
Authors: Jackson A. G. 
Published: February 2005

AbstractIn general, diffraction patterns from the higher‐order Laue zones are shifted with respect to the zero‐order pattern. Expressions for the shift (t) have been derived in terms of the indices [u, v, w] of a zone, the interplanar spacing (H), and a reciprocal lattice vector [gL (hkl)] in a holz. The resulting vector possesses the direction of t in terms of a zolz reciprocal lattice vector and has a magnitude which is a fraction of that of the zolz vector. Hence, the calculation of t allows quantitative determination of the location of specific planes in a holz with respect to the zolz, thus simplifying the determination of plane indices consistent with those used in the zolz. The expressions for determining t for cubic, hexagonal close‐packed (hep), tetragonal, orthorhombic, and monoclinic crystal types are presented in a table and, when applied, allow calculation of t expressed as a fraction of a zolz vector. An example for graphite is presented to illustrate the use of the equation, and t vectors for several zones for the simple cubic system are tabulated.
Electron microscopic analysis of residual asbestos remaining in preparative vials following bleach digestion
Authors: Corn Carolyn J. , Williams Marion G. , Dobson Ronald F. 
Published: February 2005

AbstractA recurring question that concerns researchers who use digestion techniques for the electron microscopic study of asbestos and ferruginous body (FB) load in tissue is: “Do appreciable numbers of the total fibers or FBs remain adhered to the walls of preparative vials after digestion?”A test series was devised to evaluate the fiber and FB content remaining in digestion vials (glass or plastic) as well as the effectiveness of removing these particulates through variations in the rinsing procedure. The material used for all studies was digested lung tissue from a former amosite asbestos worker. The digestion procedure was based on the bleach technique of Smith and Naylor (Am. J. Clin. Pathol.: 58:250–54, 1972), as modified by Williams et al. (J. Toxicol. Environ. Health:10:627–628, 1982). Aliquots (1.5 ml) of the digests were used to create reproducible standards. These were placed in either the clean glass or polystyrene vials that had been cut to fit in an AMRAY 1000A scanning microscope interfaced with an X‐ray energy dispersive analysis system. The aliquots were allowed to remain in the vials for 10 min or 24 h before rinsing was initiated. Aliquots used for the glass vials contained 5.1 × 106 fibers and 20 × 103 FBs, while aliquots for the polystyrene vials contained 6.9 × 106 fibers and 64 × 103 FBs.The maximum errors encountered for the glass and polystyrene vials were, respectively, 0.094% and 0.12% for fibers and 0.0098% and 0.0084% for FBs and are considered small when compared with potential sources for errors in the other stages of the preparative techniques. Also, it was concluded that if at least three thorough rinses are applied, the loss was minimal in either the glass or polystyrene vials.
Steedman's polyester wax embedment and de‐embedment for combined light and scanning electron microscopy
Authors: Norenburg Jon L. , Barrett J. Michael 
Published: February 2005

AbstractSteedman's polyester wax mixture is a good, general‐purpose histological embedding medium that is suitable and convenient to use when it is desirable to combine light microscopy with scanning electron microscopy (SEM). A range of properties recommend this wax: it has a low melting temperature (37°C), is readily soluble in most dehydrating agents, results in negligible tissue shrinkage, preserves tissue antigenicity, and may even be used as a solvent for fixative agents. We prepare and embed tissues in polyester for light microscopy much as they would be for paraffin wax. For SEM, the block surface is micro‐ or ultraplaned, utilizing, respectively, a standard rotary microtome with razor blade knives or an ultramicrotome with glass knives. The block is de‐waxed in absolute alcohol and then taken to critical point drying. Similarly, sections mounted on coverslips or glass slides may be brought to the SEM after removing the wax. This enables one to bring to the SEM relatively large block faces or sections with good control over orientation. We find the results to be superior to similar procedures employing paraffin. We believe it to be more versatile and equivalent or superior to a variety of other techniques designed to gain access to the interior of tissues with SEM.
Geometric analysis of surface resonance conditions in reflection high energy electron diffraction
Authors: Peng L. M. , Cowley J. M. 
Published: February 2005

AbstractA three‐dimensional analysis in reciprocal space is used to analyse reflection high energy electron diffraction (RHEED) patterns. Particular emphasis is placed on investigating the surface resonance phenomenon, the resonance conditions, and the diffraction mechanisms. The surface resonance regions defined by the resonance beam threshold conditions are related to the limits for the specular reflection spot in the diffraction pattern. The introduction of an Ewald sphere of varying radius is shown to be useful in understanding the surface phenomenon. Simulations based on the geometric theory, taking account of the surface refraction effect, describe very well the RHEED pattern geometry from the (111) surface of a platinum single crystal.
Comparison of Two Digestive Techniques for Preparation of Vascular Elastic Networks for SEM Observation
Authors: Crissman Robert S. 
Published: February 2005

AbstractTwo digestion procedures are now available to expose and isolate networks of vascular elastic fibers for three‐dimensional SEM observation. This study was designed to observe and elucidate the differences between the two types of digestion (sodium hydroxide vs. formic acid) and the differences between the two types of dehydration (ethanol‐critical‐point drying vs. freeze drying) used in each procedure. Canine venous valve segments, containing delicate networks of elastic fibers, and femoral arteries, containing large elastic lamellae, were used to compare the effects of the digestion and dehydration procedures on two types of vessels with different content and organization of elastic tissue. Results indicated there was no significant difference in the architecture of the elastic networks of either vessel based on the method of digestion. The major architectural changes in the elastic networks occurred as a result of the dehydration procedure used following digestion. Freeze drying is probably the best for arterial specimens due to their prominent lamellae, which give added support to maintain their normal architecture. It is suggested that both methods of dehydration be used on corresponding venous specimens containing delicate elastic networks. In this way, the investigator can benefit from the advantages of each method and overcome their respective disadvantages to get a more accurate picture of the three‐dimensional architecture of these delicate networks.
Practical Aspects of Lattice Imaging of Cellulose
Authors: Kuga Shigenori , Brown R. Malcolm 
Published: February 2005

AbstractThe lattice imaging technique for cellulose, a typical electronbeam‐sensitive material, was developed by using a conventional 120 kV electron microscope. Routine procedures for specimen preparation and high resolution, low dose electron microscopy are described in detail. A new, simple method was introduced for the preparation of a Formvar micronet to support the thin carbon film. The lattice imaging technique was successfully applied to algal celluloses as well as bacterial cellulose, which is composed of much smaller crystallites than the former. Digital image processing was found to be effective in enhancing the lattice images. The bacterial cellulose ribbon contained crystallites 10–25‐nm wide, which is much greater than the basic unit of cellulose fibril extruded from the cell surface. This shows that unit fibrils can fasciate with each other, merging into a single crystallite.
Postreplication labeling of E‐leaflet molecules: Membrane immunoglobulins localized in sectioned, labeled replicas examined by TEM and HVEM
Authors: Dinchuk Joseph E. , Johnson Timothy J. A. , Rash John E. 
Published: February 2005

AbstractConventional freeze‐fracture techniques were combined with immunogold labeling and with plastic embedding and sectioning to analyze the distribution of membrane immunoglobulins (mIgs) and their associated intramembrane particles (IMPs) in E‐face replicas of murine B‐lymphocyte plasma membranes. Immunogold labels were applied to cells after the process of freeze‐fracture and replication. Conventional stereoscopic transmission electron microscopic examination of sectioned, labeled replicas (SLRs) revealed that the gold‐labeled mIgs were bound to and localized on the outer leaflets of split and replicated membranes. The gold labels were attached to the external determinants of the mIg molecules, which were retained beneath and contiguous with the replicated E‐faces. The mIgs were also localized on the external surface of unreplicated microvilli. In addition, thick sections examined by high‐voltage transmission electron microscopy (HVEM) revealed large expanses of replica with well‐resolved IMPs. mIgs colocalized with small‐diameter (<60 Å) IMPs in E‐face replicas of B‐lymphocytes whose mIgs were patched by anti‐immunoglobulin. Thus, postreplication E‐surface labeling of split and replicated membranes is a high‐resolution technique that is suitable for the study of membrane protein distribution in E‐face replicas and contiguous nonreplicated tissue.
Quantitative electron microscopy applied to traditional Chinese medicine
Authors: Liu Hepei , Tang Dangsheng , Hou Yanming , Yang Yun , Wang Shulan 
Published: February 2005

AbstractIn the present report, quantitative electron microscopy is applied to the basic theory of traditional Chinese medicine (TCM). The theory of TCM indicates that pi (spleen in TCM) has important roles in human health. One such function of the pi is nourishing the muscles, and our work examines the ultrastructural basis of the pi actins in this role. The number of mitochondria of skeletal muscle per area was measured and analyzed. The results indicate a significant decrease in the number of mitochondria with normal structure and a significant increase in the number of mitochondria with abnormal structure in piqixuzheng (spleen energy deficiency in TCM) rats. Such changes are thought to reduce the energy supply of the muscles. After treatment with sijunzitang (herbs which invigorate functioning of the pi), the data do not show a significant difference when compared with normal rats. It is considered that the energy metabolism of the cells is one of the functions of pi.
Effects of the coherence of illumination on electron microdiffraction pattern intensities
Authors: Zhu Jing , Peng L.‐M. , Cowley J. M. 
Published: February 2005

AbstractMicrodiffraction is capable of revealing the local structure within an area of the specimen consisting of only a few, or a few tens of, unit cells. However, the extent to which the diffraction pattern intensities can show the local structure depends strongly on the coherence of the illumination. If the coherence width of the illumination is smaller than the diameter of the electron probe at the specimen level, the details within the diffraction spots, which indicate deviations of the local structure from the periodicity of the crystal, will be lost. The differences in the amount of spot splitting observed in microdiffraction patterns from out‐of‐phase domain boundaries, observed with two instruments, are attributed to differences in the effective source sizes.
New cryoultramicrotome with a feedback‐advance system
Authors: Wolf Bernhard 
Published: February 2005

AbstractCryoultramicrotomy is gaining in significance and use as technical improvements are made. In comparison with epoxy resin procedures, cryopreparations are more rapid; there is only a negligible loss of material and thus antigenicity is well preserved.The present work contains some newly developed details for the exact determination of the advancement of the sample in the direction of the knife in a microtome. It is a software‐controlled ultramicrotome advance drive system with feedback regulation as well as repeatedly patented devices for advancement sensors.
Electron microscopic visualization of fatty acids in tissues
Authors: Blanchette‐Mackie E. Joan , Amende Lynn M. 
Published: February 2005

AbstractLong‐chain fatty acids are important structural and metabolic functions in tissues. Fatty acids are derived from triacylglycerol‐rich particles in capillaries (chylomicrons and very‐low‐density lipoproteins) and from triacylglycerol stored in cells (lipid droplets) by the hydrolytic activity of tissue lipases.The identification and localization of fatty acids in tissues has been considered difficult to obtain by using conventional ultrastructural techniques. However, structural findings from our studies on fatty acid transport in tissue became interpretable due to the use of many overlapping techniques. We present here these ultrastructural techniques developed to study fatty acids in tissues and review data which demonstrate lipase activity and fatty acid production from triacylglycerol in aldehyde‐fixed tissue. Accumulations of fatty acid in tissue are present as lamellar structures with periodicity of 40–50 Å in sections of resin‐embedded tissue and as hydrated myelin figures in freeze fracture replicas of unfixed and fixed tissue. Finally, a new method, using the ionization properties of fatty acids combined with freeze fracture, locates these amphipathic molecules to leaflets of membrane bilayers.
Chromatin organization in detergent‐lysed chicken erythrocyte nuclei
Authors: Seki Shuji , Nakamura Takashi , Suma Fumihiko , Murakami Masao , Mori Shigeru , Oda Takuzo 
Published: February 2005

AbstractA method for electron microscopic demonstration of supranucleosomal (20–30 nm chromatin) fiber loops was developed. Chicken erythrocytes were treated with varying concentrations of detergents, such as Joy®, sodium N‐lauroyl sarcosinate, and sodium laurylsulfate, and then fixed with a formalin solution. The fixed cells were centrifuged onto an electron microscope grid, followed by staining and metal shadowing. Thin‐sectioned specimens of the fixed cells were prepared routinely. Although supranucleosomal fiber loops could be observed when any one of these detergents was used, Joy gave the best result. Electron micrographs of rotary‐shadowed specimens of erythrocyte ghosts formed by treatment with a low concentration (0.07–0.11 w/w%) of Joy showed a halolike, radial arrangement of supranucleosomal fiber loops around the ghost cells. The width of the halo was about 3μm. By increasing the detergent concentration (∼0.18% Joy), nucleosome fibers and naked DNA appeared and increased in number, indicating that the supranucleosomal fibers were disassembled by the action of the detergent. Thin‐sectioned specimens of cells treated with 0.09% Joy showed granulofibrillar chromatin radially dispersed from the nuclear cage. The fibers were thought to be identical with the supranucleosomal fibers observed in the rotary‐shadowed specimens.
High‐resolution electron microscopy and its applications
Authors: Li F. H. 
Published: February 2005

AbstractA review of research on high‐resolution electron microscopy (HREM) carried out at the Institute of Physics, the Chinese Academy of Sciences, is presented. Apart from the direct observation of crystal and quasicrystal defects for some alloys, oxides, minerals, etc., and the structure determination for some minute crystals, an approximate image‐contrast theory named pseudo‐weak‐phase object approximation (PWPOA), which shows the image contrast change with crystal thickness, is described. Within the framework of PWPOA, the image contrast of lithium ions in the crystal of R‐Li2Ti3O7 has been observed. The usefulness of diffraction analysis techniques such as the direct method and Patterson method in HREM is discussed. Image deconvolution and resolution enhancement for weak‐phase objects by use of the direct method are illustrated. In addition, preliminary results of image restoration for thick crystals are given.
Application of convergent beam electron diffraction in the structural study of high‐temperature superconducting oxides
Authors: Zou X. D. , Yang C. Y. , Zhou Y. Q. 
Published: February 2005

AbstractConvergent beam electron diffraction (CBED) is a powerful technique for symmetry study of crystal. It has widespread application in physics and material sciences, as demonstrated in a recent superconducting oxide study. Using this technique, we have studied Ba‐La‐Cu‐O superconductors with a transition temperature of about 40°K and Ba‐Y‐Cu‐O superconductors with a critical temperature (Tc) of about 90°K. We have found that in Ba‐La‐Cu‐O superconductors the superconducting phase La2−xBaxCuO4−y has a distorted K2NiF4‐type structure and the space group Fmmm. The two other phases in Ba‐La‐Cu‐O superconductors have also been studied. In our Ba‐Y‐Cu‐O superconductors, the Ba2YCu3O7−x compound, which is responsible for 90°K superconductivity, has two different space groups: An orthorhombic space group Pmmm and a tetragonal space group P4mm or P4/mmm.
High‐resolution electron microscopy and domain structures of pentagonal frank‐kasper phases
Authors: Ye H. Q. 
Published: February 2005

AbstractThe Laboratory of Atomic Imaging of Solids is dedicated to the direct imaging of materials in various fields of solid‐state sciences at the atomic or molecular level. The main programs of this laboratory are briefly described, including quasicrystals, new phases and microdomains in Frank‐Kasper phases, suboxides of metals, catalysts, minerals found in China, and molecular structure of organic substances. A recent systematic investigation of domain structures consisting of juxtaposed icosahedral columns is also presented.
Some nanostructural features in ceramics
Authors: Wen Shulin 
Published: February 2005

AbstractNanostructural features in some ceramics have been discussed and reviewed. Based on our research results and recent published investigations, many topics, such as grain, grain boundary, interface film, grain boundary engineering, microcrack, microdomain, nanodomain, domain boundary, and phase transformation, etc., have been dealt with; and many materials, such as Si3N4, β″‐Al2O3, MgO, SiC, (Hg, Cd) Te, BNN, ZrO2, PLZT, CdSe, Ca10(PO4)6, (OH)2, etc., have been involved. The results are important to understand the relation between the structure and property of materials and to improve the materials' technology.
Standardless EDS analysis of bulk and thin specimens
Authors: Wu Ziqin 
Published: February 2005

AbstractA direct relationship between the x‐ray intensity ratio and the concentration ratio for bulk and thin specimens has been established by use of a revised full‐diffusion model of electron scattering. The suitable ionization cross section, the most important parameter influencing the accuracy of the calculated Cliff‐Lorimer factors, has been found after comparing the experimental intensity ratio I(L)/I(K) of eight elements (from Ge to Sn) and I(M)/I(L) of six elements (from Sm to Bi) with the calculated values. The quantitative standardless EDS analysis of bulk samples obtained by this direct method is more satisfactory than the commercial indirect method which gives the composition through ZAF correction after calculating the intensity factors of pure elements. The quantitative standardless analysis of thin samples has been improved by the suitable cross section significantly. This method has been applied to the analysis of film on substrate either without any common element or with one common element (P‐Si glass film on Si). It has also been used to calculate the intensity factors of pure bulk samples and the backscattering correction factor in Auger electron spectroscopy.
Utilization of digital image processing to study dynein arms (ATPase) in normal and immotile cilia
Authors: Kennedy John R. , Dunlap John R. , Bunn Rod D. , Edwards David F. 
Published: February 2005

AbstractTracheal ciliary cross sections were examined with scanning transmission electron microscopy and the resultant images were digitized for image enhancement. A gray‐scale histogram of each ciliary image was produced and manipulated to enhance the image for dynein arms. Tracheal epithelial tissue from the pig, rabbit, and dog, including dogs with immotile cilia syndrome, was examined by using this technique. Tissue from each animal was fixed with each of three different fixatives and sections were evaluated for preservation of dynein arms. The same fixative did not consistently provide optimal fixation for ciliary dynein arms in all three species examined. Each species, therefore, must be evaluated to determine the optimal fixative for preservation of normal ciliary ultrastructure. Digital image processing provides a mechanism for enhancing dynein arms in situ without the need for addition of special stains or the use of techniques such as image summation. With this technique it has been shown that about two‐thirds of outer dynein arms are partially or completely missing on cilia from dogs with immotile cilia syndrome.
Object‐marking, a bridge between light and analytical electron microscopy for particles characterization
Authors: Dumortier P. , De Vuyst P. 
Published: February 2005

AbstractIn problems of air or water pollution, or in evaluation of exposure to pathogenic dusts from biological specimens ( e.g., asbestos fibers) some typical particles can be used as tracers. As far as they have sufficiently typical properties (shape, color, anisotropy,…) particles are rapidly recognized and quantified by light microscopy (LM), even if they are very scarce or dispersed among large amounts of unsignificant ones. For accurate characterization, analytical electron microscopy (scanning or transmission) is required, but cannot be efficiently applied for low concentrations of particles. A technique using a high precision object‐marker under LM has been developed in the past by Jedwab (1975) to be used with SEM, but there is actually no equivalent for TEM. Such a technique is proposed in this paper. Its major interest resides in the greater amount of analytical data available for one single particle (high magnification morphology, crystallographic structure, chemistry). Practical results were obtained with asbestos fibers and bodies recovered from biological specimens, but the technique can be extended to many other problems concerning micron‐sized particles.
Evaluation of high‐resolution electron microscopy as a method for studying Y‐Ba‐Cu‐O superconductors
Authors: Krakow William , Shaw Thomas M. 
Published: February 2005

AbstractHigh‐resolution transmission electron microscopes operating at 300 and 400 kV were used to investigate the crystallography and microstructure of the perovskitelike YBa2Cu3O7−x. In this paper, we evaluate the performance attainable with these microscopes both empirically and by computer modelling. Based upon the assumption that oxygen may be a key to superconductivity properties, we have also investigated the visibility of the oxygen sites as well as the heavier yttrium and barium ion positions and the lighter Cu atom positions. We propose a scheme for observing different twin orientations in these structures and hence the oxygen atom positions seen in projection for the [100] and [010].Our observations of both thick and thin regions of Y‐Ba‐Cu‐O materials are reported as well as the problems of adjusting microscope parameters and specimen alignment to obtain interpretable images. We also give a preliminary report on the effects of heat treatment as seen in high‐resolution micrographs to assess disorder of the heavy atoms and oxygen vacancies.