bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential leucocyte counts: A comparison of results using light and electron microscopy
Authors: Gillett R. , Hancock P. M. , Williams D. M. , Hill M. W. 
Published: August 2011

SUMMARYA method is described for handling leucocytes from an inflammatory peritoneal exudate prior to electron microscopy, which allows differential counts from ultrathin sections to be made. The results of counts from ultrathin sections, viewed on the electron microscope, are compared with samples from the same cell populations prepared on a cytocentrifuge and counted by light microscopy. The results from several cell populations of widely different compositions show clearly that with suitable care taken over preparation and orientation, ultrathin sections can yield comparable differential counts to those obtained by standard light microscope procedures. Possible sources of error are discussed and the advantages of ultrastructural counting assessed. The method has a wide application wherever accurate differential counts are required from cell suspensions processed for electron microscopy.
Scanning electron and light microscope correlation of individual human bone marrow cells before and after culture in nutrient agar
Authors: Lytton D. G. , Yuen E. , Rickard K. A. 
Published: August 2011

SUMMARYThis study was undertaken with the aim of identifying the different cell types found in human bone marrow by examining their surface morphology. In an attempt to obtain a homogeneous cell population, cells were both fractionated by discontinuous albumin density gradient centrifugation (DADGC) and selectively grown in nutrient agar. Both cell preparations underwent the critical point drying technique before examination under both the scanning electron microscope (SEM) and subsequently the light microscope (LM). When the SEM image of individual cells was compared with the corresponding LM image, it was not easy to identify the different cell types, because of the shrinkage and distortion that occurred during their preparation. The shrinkage observed under the SEM amounted to a 45% reduction in mean cell diameter. This shrinkage was confirmed by comparing the SEM and LM images of the same cell. Although shrinkage occurred throughout the dehydration sequence, critical point drying was responsible for a 25% reduction in mean cell diameter. Furthermore, direct observation under LM of fixed cells drying in air from ethanol, revealed visible contraction of the cell and distortion of the cell membrane. We assume that a similar morphological change occurred during critical point drying. We conclude that the shrinkage and distortion, caused by the dehydration process involved in SEM preparation, severely limit the value of a study of surface morphology by SEM in the identification of the different cell types found in human bone marrow.
Techniques Utilizing Real Time Stereo Scanning Electron Microscopy In The Microdissection Of Biological Tissues
Authors: Barber V.C. , Emerson C.J. 
Published: August 2011

SUMMARYThe use of the scanning electron microscope (SEM) for the microdissection of biological tissue is described. The dissections were accomplished by the use of electrolytically pointed needles that were positioned in a simply constructed holder. The operations were viewed using real time stereo SEM, and recorded on videotape. Various methods for photographing the videotape recordings are outlined.
Lead And Uranium Stain Artefacts In Electron Microscopy: A Technique For Minimizing Their Occurrence
Authors: Thaete Larry G. 
Published: August 2011

SUMMARYA new technique is presented which significantly reduced the occurrence of artefacts by eliminating the air‐stain interface when staining thin sections of biological material. It is designed for simultaneous treatment of large numbers of samples. The experiment described deals mainly with the specific staining problems encountered when using grids coated with Formvar.
A Scanning Microinterferometer With Correction Of Errors Caused By Overlapping ‘Ghost’ Images
Authors: de Jong J. E. De Josselin , Loeve J. , Richter H. , de Sterke H. , Ploem J. S. 
Published: August 2011

SUMMARYAn experimental setup has been built to correct the errors caused by overlapping‘ghost’ images when scanning and integrating measurements are carried out with the Jamin‐Lebedef interference microscope. First a reference field with the object, producing the‘ghost’ image, is scanned and the values of the optical path difference (OPD) of each point in the reference field are stored in a computer. Subsequently, the OPD of the object to be measured is calculated for each point by adding the measuring result to the average OPD of five points, located around the corresponding point in the reference field. The applicability of the setup has been tested by measurements with Sepharose beads, Hela cells and the Zeiss microinterference refractometer. The difference between measurements on the same object with and without overlapping‘ghost’ image was about 10%. The reproducibility was tested by repeated measurements on the same cell whereby a standard deviation of 1·1% was found.
Optimized Energy Dispersive X‐Ray Microanalysis With A Siemens Elmiskop 102 Electron Microscope
Authors: Hutchison J. L. , Lucas J. H. 
Published: August 2011

SUMMARYThis paper describes modifications made to the objective lens of a Siemens Elmiskop 102 electron microscope which enable a Kevex Si(Li) detector to be brought to within 20 mm of the optic axis, and which give rise to a relatively‘clean’ X‐ray microanalysis system. The modifications do not affect the performance of high resolution, double‐tilt capability of the instrument.
Some Microstructural Observations Of Transformations In A Copper‐Titanium Alloy
Authors: Ecob Roger C. , Bee John V. , Ralph Brian 
Published: August 2011

SUMMARYThis paper describes the microstructures observed when a dilute copper‐titanium alloy (Cu‐4wt%Ti) is isothermally transformed. The β phase which forms on transformation is observed in both Widmanstätten and cellular morphologies. It is shown, using light and electron microscopy, that some Widmanstätten plates become the nuclei of cellular plates and that there is often an association between cellular plates of the β phase and more than one twin variant of the matrix α. Dislocation arrays on the α/β interfaces have been resolved and a continuity of this structure between the migrating transformation interface and dislocation arrays on the habit plane has been found.
Precipitation Procedures For Sodium, Potassium And Chloride Localization In Leaf Cells Of The Halophyte Suaeda Maritima
Authors: Harvey Diana M. R. , Flowers T. J. , Hall J. L. 
Published: August 2011

SUMMARYAttempts have been made to localize sodium and potassium with antimonate and cobaltinitrite reagents in Suaeda leaf segments by rapid aqueous and freeze‐substitution precipitation procedures and to localize chloride by freeze‐substitution precipitation with silver ions. Substantial sodium losses occurred from the tissue during both types of preparation although potassium and chloride losses were considerably reduced by the use of freeze‐substitution when compared with the rapid aqueous procedures. The losses during freeze‐substitution resulted from the required use of ethanol as substitution solvent (rather than acetone or diethyl ether, in which the reagents were much less soluble). Analytical electron microscopy showed that silver and cobaltinitrite specifically precipitated chloride and potassium respectively, but antimonate did not specifically precipitate sodium. The vacuoles were important sites of silver and antimonate deposits, although the chloroplasts were the major sites of cobaltinitrite localization. The value of these techniques in ion localization studies is discussed.
Digital Picture Analysis In Microphotometry Of Biological Materials
Authors: Zimmer Hans‐Georg 
Published: August 2011

SUMMARYAutomatic evaluation of two‐dimensional thin‐layer‐chromatograms exemplarily demonstrates the applicability of signal processing, image analysis, and pattern recognition to microphotometry by an enlarged dynamic range of the photometer, improved reproducibility by noise reduction, discrimination between objects and background, feature extraction and automatic classification of the results. Emphasis is put on simple procedures which are tested in routine work and can be implemented on minicomputers.
Spectral Changes Of The Fluorescent Acriflavine‐(Feulgen) Dna Dye Complex At Different Temperatures: Application Of A New Cryostat For Measurements In Reflected And Transmitted Light
Authors: Tiffe H. W. , Matzke K. H. , Thiessen G. 
Published: August 2011

SUMMARYThe fluorometric behaviour of cellular objects is influenced during excitation by two nearly independent phenomena: (1) by the photochemical reaction of the DNA/AF dye complex, and (2) by the energy transfer among several DNA/AF dye complexes. Both processes show a distinct temperature‐dependent behaviour and can therefore be characterized by the analysis of the fluorescence spectra at different temperatures.All microfluorometric measurements were performed with a self‐constructed cooling device. The cryostat permits measurements of the cellular fluorescence within a range of temperatures between 4 K and 300 K. The cooling unit operates in accordance with the‘Continuous Flow Principle’ and allows the application of objectives up to a numerical aperture of 0·6.
An Account Of Electron Optics In The Cavendish Laboratory And Related Developments
Authors: Hawkes P. W. 
Published: August 2011

SUMMARYContributions to many aspects of geometrical optics and digital image processing have originated in the Electron Microscopy Section of the Cavendish Laboratory. An account of these is given in the opening sections, in the context of related contemporary work, with particular attention to quadrupoles and high frequency lenses and to the phase problem and image handling. Subsequent developments, with especial emphasis on very recent progress, are briefly reviewed in the penultimate section.
X‐Ray Microanalysis
Authors: Duncumb P. 
Published: August 2011

SUMMARYOver the past 30 years the electron probe microanalyser has progressed from a laboratory concept to a highly sensitive and well‐engineered instrument in use in various forms all over the world. Ellis Cosslett has been associated with this development for 25 of these years, with a particularly fruitful period in his laboratory during the late 1950s and the decade following. The subject has always illustrated well the interdisciplinary nature of instrument development, with the engineering design complemented by the physical theory of analysis and by the user disciplines represented in its application. This paper traces briefly some of the developments in the technique at various stages from designer to end‐user, with particular reference to the part played by Cosslett's laboratory and by others in the Cambridge area.
Electron microscopic appearances of rapidly frozen lung
Authors: Mazzone Robert W. , Durand Carlita M. , West John B. 
Published: August 2011

SUMMARYAnalysis of pulmonary structure‐function relationships by microscopy requites that the lung be fixed under carefully controlled physiological conditions, since lung structure is extremely responsive to the relationship between airway and vascular pressures. Unfortunately, standard post‐mortem fixation techniques leave some doubt as to the exact relationship between these pressures during fixation. This problem can be circumvented by stabilizing lung structure by rapid freezing under carefully controlled physiologic conditions. Using ethylene glycol in a freeze substitution technique we have developed procedures which yield a degree of preservation compatible with the high degree of resolution of the electron microscope. These can be used to obtain a more detailed understanding of pulmonary structure‐function relationships under well‐defined physiological conditions.
A method for polishing shale for vitrinite reflectivity measurements
Authors: Simpson W. B. 
Published: August 2011

SUMMARYA method of polishing friable rock samples is proposed in which the usual lubricating agent, water or isopropyl alcohol, is eliminated and the sample polished dry.The plucking usually seen with water‐sensitive samples is not seen and scratching of the surface is not a problem.The reflectivity of vitrinite in a coal is compared when polished dry and by the usual wet method and is found to be similar in both cases.
A computerized graphical method for analysing stereo photo‐micrographs
Authors: Minter F. J. , Piller R. C. 
Published: August 2011

SUMMARYA method has been devised for presenting three‐dimensional information from stereo pairs of electron micrographs in a graphical form. From this it is possible to obtain information about the spatial distribution of defects or precipitates, the existence and depth of denuded zones, the thickness, and the surface topography of thin foils examined by transmission electron microscopy.
Cross‐Sectional Transmission Electron Microscopy For Polycrystalline Silicon Films
Authors: Oppolzer H. , Falckenberg R. , Doering E. 
Published: August 2011

SUMMARYThe grain structure and the surface roughness of undoped polycrystalline silicon films were studied by TEM of cross‐sectional specimens. The grain diameter parallel to the surface could be directly determined as a function of the distance from the interface. An almost linear increase was found for all deposition temperatures between 923 K and 1123 K. For low deposition temperatures, the grains are columnar, while for high temperatures they are equiaxed. Cross‐sectional TEM‐specimens further allow a quantitative determination of the surface roughness. The roughness is not correlated with the grain diameter at the surface. A sharp increase of the roughness at 1123 K can be explained by the disappearance of a preferred orientation of the grains.
The preparation of calibration standards for sodium, potassium and chlorine analyses by analytical electron microscopy
Authors: Harvey Diana M. R. , Flowers T. J. , Hall J. L. , Spurr A. R. 
Published: August 2011

SUMMARYAttempts were made to prepare sodium and potassium thin section standards for analytical electron microscopy by introducing, in serial concentrations, a complex between the appropriate salt and macrocyclic polyether ([15] crown‐5 for sodium and [18] crown‐6 for potassium) into epoxy resin. Of the tested salts, sodium tetraphenylborate, tetrafluoroborate and cyanide failed to produce homogeneous standards, and those standards containing sodium or potassium iodide or bromide were analytically inhomogeneous at concentrations greater than 20 meq 1−1. Only sodium thiocyanate and potassium cyanide standards were analytically homogeneous at concentrations up to 600 meq 1−1. A chlorine standard, which was analytically homogeneous at concentrations up to 1000 meq 1−1, was prepared by incorporating 1,2,4‐trichlorobenzene into an epoxy resin.
Dimensions of active cytochrome c oxidase in reconstituted liposomes using a gold ball shadow width standard: a freeze‐etch electron microscopy study
Authors: Ruben George C. , Telford John N. 
Published: August 2011

SUMMARYThe preparation and characterization of a distribution of gold balls on a thin, flat carbon film is described. The relation of the platinum carbon shadow width distribution means to a gold ball size is reported.Freeze‐etched cytochrome oxidase vesicles and gold ball calibration grids were simultaneously shadowed with platinum/carbon. The shadow width distribution of the cytochrome oxidase located in and spanning the membrane was measured. The membrane fracture face edge and cross‐fractured bilayer membrane edge were also measured.Dimensions of the cytochrome oxidase were found to be 5·8 ± 0·3 nm in diameter parallel to the membrane and 8·2 ± 0·3 nm long across the membrane. The bilayer membrane dimensions were 3·0 ± 0·3 nm for the half bilayer and 5·8 ± 0·3 nm for the cross‐fractured bilayer membrane edge thickness. The length of the cytochrome oxidase was observed to span the bilayer membrane. Previous X‐ray diffraction measurements on similar hydrated liquid crystalline artificial membranes were found to be in good agreement with the freeze‐etched results.Membrane widths from thin‐sectioned cytochrome oxidase vesicles were measured and found to be 5·8–5·9 nm in non‐post‐stained sections. Post‐staining with uranyl acetate and/or lead citrate was shown to increase this average thickness.The technique of freeze‐etching electron microscopy in conjunction with the gold ball shadow width calibration experiment has been shown to provide accurate and precise measurements of membranes and a functional intramembrane protein in a hydrated non‐crystalline sample.
Surface studies in a UHV field emission gun scanning electron microscope
Authors: Venables J. A. , Janssen A. P. , Akhter P. , Derrien J. , Harland C. J. 
Published: August 2011

SUMMARYRecent instrumental advances have enabled scanning electron microscopy using a field emission gun (FEG) to be combined with an ultra high vacuum specimen chamber. The resulting instrument, the UHV‐FEG‐SEM, allows high spatial resolution microstructural and micro‐analytic information to be obtained reliably from clean surfaces for the first time.Such an instrument has been installed and developed at the University of Sussex. It incorporates SEM at ∼5 nm resolution, scanning Auger microscopy at ∼30 nm resolution, and various diffraction techniques, including RHEED and electron backscattering pattern (EBSP) techniques, at (lateral) resolutions which can approach 10 nm. The work function can also be measured microscopically as demonstrated in this paper. Combined with facilities for in situ cleaning and molecular beam deposition, these techniques represent a considerable improvement in our ability to study surface and near‐surface phenomena on a microscopic scale.Examples of recent work on technique development, including work‐function measurement and backscattering patterns, are described. Recent applications to metal and semiconductor systems are described, including the crystal growth of Ag on Si (111) and Mo (100), the composition profiles of GaAs lasers, and adsorbed Cs layers on tungsten.
Observations on deformed electrolytically deposited Ni3P
Authors: Donovan E. , Stobbs W. M. 
Published: August 2011

SUMMARYElectrodeposited amorphous Ni3P was deformed in situ on a brass substrate. The films, when observed in the electron microscope, showed both light and dark bands in bright field images which were not seen in undeformed material. It is proposed that the origin of this contrast is a change of both density and structure of the material within the deformation bands.
Internal and platinum initiated crystallization in Na2O.2 CaO. 3 SiO2 glasses: early stages of growth
Authors: Gonzalez‐Oliver C. J. R. , James P. F. 
Published: August 2011

SUMMARYTransmission electron microscopy at 100, 900 and 1000 kV was used to study the early stages of growth of internally nucleated crystals of the phase Na2O.2 CaO. 3 SiO2 (‘NC2S3’) in glasses close to the NC2S3 composition. Glass samples were partially crystallized by heat treatment in the range 833–873 K and thin foils for electron microscopy were prepared by ion beam thinning. The phase identified by electron diffraction from a number of small crystals (the low temperature form of NC2S3) was the same as that determined by X‐ray diffraction of fully crystallized glass ceramics. Selected area diffraction and bright and dark field microscopy showed that in the early stages of development the crystallization centres were essentially single crystals but contained a significant concentration of defects. These crystals were nucleated, probably homogeneously, at temperatures higher than the well‐established low to high reversible polymorphic transformation of the NC2S3 crystalline phase. In a glass of similar composition to which platinum was deliberately added there was clear evidence for heterogeneous nucleation of NC2S3 crystals on platinum particles distributed in the glass. Also the contact angle between NC2S3 crystals and the rounded platinum particles could be measured directly.
High resolution studies of glass‐crystal interfaces
Authors: Krivanek O. L. 
Published: August 2011

SUMMARYHigh resolution electron microscopy has been used to image intergranular glassy phases in sintered and hot‐pressed nitrogen ceramics, and the Si‐SiO2 interfaces important in MOS devices.The thin intergranular glassy phases were found at most grain boundaries in all liquid‐phase sintered or hot‐pressed ceramics examined. Silicon carbide sintered by a solid state diffusion process, however, contained no such phases.Si‐SiO2 interfaces have been examined in cross‐section at about 0ṁ3 nm resolution. The images show that the transition from the Si crystal to the amorphous oxide was abrupt, but that there were 0ṁ3‐0ṁ5 nm high hills on the Si surface, separated by 2–4 nm, and long‐range undulations of 0ṁ6‐0ṁ8 nm height and 20–50 nm periodicity. Ultra‐thin (3 nm) oxides were also examined and were found to be uniform in thinkness, indicating that the roughness at the Si‐SiO2 interfaces is initially caused by irregularities on the original, unoxidized Si surface.
The initial stages of ordering in alloys studied by electron diffraction and high resolution microscopy
Authors: Tendeloo G. Van 
Published: August 2011

SUMMARYThe combined use of selected area electron diffraction and high resolution electron microscopy can provide important information about the microstructure of materials. Both techniques have been applied to study the ordering behaviour in a number of alloys. The ordering process is not always straightforward and mostly intermediate long period modulated structures are formed. Using dark field high resolution electron microscopy the ordering sequence as well as the structure of the intermediate phases have been established for Au4Mn and Au5Mn2. For Ni4Mo the high resolution observations provide new information about the ordering mechanism in its very earliest stages.
Protein staining methods in quantitative cytochemistry
Authors: Tas Johan , Ploeg Mels van der , Mitchell JohnP. , Cohn NormanS. 
Published: August 2011

SUMMARYThe chemical action and practical application of the Naphthol Yellow S, Alkaline Fast Green, Coomassie Brilliant Blue, Dinitrofluorobenzene and some lesser known protein staining methods have been surveyed with respect to their potentialities for quantitative cytochemical analyses. None of the dyes can be said to bind to any specific protein or group of proteins, but each may be used to analyse the presence of one or more particular amino acid residues. For the cytophotometric measurement of the ‘total protein content’ of individual cells and cell organelles the covalent binding Dinitrofluorobenzene and the electrostatic binding Naphthol Yellow S can properly be used. Fast Green FCF, applied at alkaline pH, binds electrostatically to the basic amino acid side chains of strongly basic proteins only but not in a quantitative (stoichiometrical) way. Coomassie Brilliant Blue, recently introduced to protein cytochemistry, may be useful for quantitative purposes. The combined Feulgen‐Pararosaniline(SO2)/Naphthol Yellow S and Dinitrofluoro‐benzene/Feulgen‐Pararosaniline(SO2) methods enable the simultaneous cytophotometric analysis at two different wavelengths for protein and DNA within the same microscopical preparation.