bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Preservation Of Surface‐Associated Micro‐Organisms Prepared For Scanning Electron Microscopy
Authors: Garland C. D. , Lee Adrian , Dickson M. R. 
Published: August 2011

SUMMARYScanning electron microscopy (SEM) has become a popular means of studying micro‐organisms which associate with surfaces. However, as yet no detailed examination has been made of the influence of specimen preparation on the number of organisms finally seen on the SEM screen. In this investigation critical assessment is made of the influence of a wide range of preparative factors on the preservation of filamentous bacteria associated with the epithelial surfaces of rat intestine. Organisms were quantitated using a rigorous counting method (transect line analysis); statistical testing of these counts enabled the comparison of different preparative factors. The composition of the fixative was found to significantly influence the number of organisms preserved; of the fifteen fixatives studied, Karnovsky's fixative with ruthenium red best preserved surface‐associated organisms. The influence of other factors on the number and appearance of preserved organisms was also examined. These factors included the washing of specimens prior to fixation, the storage of fixed specimens, and the handling and storage of critical point dried specimens. The results are discussed with reference to the optimal methods for preparing specimens for SEM.
Domains Of Microscope Photometry In Materials Science
Authors: Piller Horst 
Published: August 2011

SUMMARYThe application of microscope photometry in non‐biological fields is reviewed. The objects in microscope photometry are micro‐particles or small areas of macro‐scopical bodies which, because of their size, cannot be examined by macrophotometry. The commonly measured properties in microscope photometry are as follows: transmittance, specular or diffuse reflectance, relative intensity of light emission by self‐luminous objects, e.g. luminescence or fluorescence, in the spectral (wavelengths) range ca. 250–1000 nm.The paper gives examples of how coloured solid bodies, e.g. gemstones and ore minerals, can be identified, rock‐forming minerals differentiated, diamonds classified, paper quality assessed, organic constituents in rocks characterized, crime detection aided, the chemistry of alloys established, and information on structural organization in inorganic and organic crystals supplemented.
Automated Microscope‐Absorption‐Spectrophotometry Of Rock‐Forming Minerals In The Range 40,000–5000 Cm−1 (250–2000 Nm)
Authors: Langer K. , Frentrup K.R. 
Published: August 2011

SUMMARYTo measure polarized absorption spectra of microcrystals of 3dn‐ion bearing silicate minerals, computer processed, microscope‐spectrophotometric methods have been developed. Absorbance, log (I0/I), can be measured with high relative accuracy (near u.v. and vis: ±0·002 to 0·001; n.i.r.: ±0·004 to 0·002), and relatively small spectral band widths are available. Hence, weak spin‐forbidden dd‐bands of 3dn‐ions can be recognized alongside spin‐allowed dd‐transitions without artificial broadening of absorption bands due to finite resolution. The smallest area from which absorption spectra can be taken is 8 μm in diameter. As one example of the many applications in mineralogy and material sciences, absorption spectra of a natural spessartine garnet, Spess69·7Alm30·0Gross0·05, containing Mn2+, Fe2+, and traces of Fe3+ as 3dn‐ions, and of a pure Mn2+‐garnet, Spess67Gross33, are presented. From these it is evident that bands in natural spessartines at ∼ 26,900, 23,200 cm−1 which were assigned to dd‐transitions in Fe3+(6), have to be reassigned to Mn2+(8). Comparison of spectra obtained with the microscopic equipment described with those obtained by means of conventional macroscopic equipment prove that the methods described produce true spectra.
Microscope Photometry In Studies Of The Molecular Structure Of Carbonized Bitumens And Pyrobitumens
Authors: Khavari‐Khorasani G. , Blayden H. E. , Murchison D. G. 
Published: August 2011

SUMMARYFour bitumens and pyrobitumens (gilsonite, grahamite, impsonite and shungite), varying considerably in their initial properties, have been carbonized over the temperature range 0–1400 °C. Reflectances of the carbonized products in air and immersion oil were measured at 546 nm using a conventional microscope photometer, and the effective bireflectances. refractive indices and absorption coefficients calculated for the samples from the reflectances. The results obtained support an earlier suggestion that the derived optical data can be used to supplement X‐ray lattice parameters as a means of tracing the general course of molecular and structural organization of organic materials when these are carbonized, viz: (a) continuously rising bireflectance and absorption coefficient with rise of preparation temperature respectively indicate progressive ordering of the aromatic lamellae and increasing average diameter of the sheets of aromatic layers forming the‘crystallites’; while (b) systematic changes of the effective refractive index point to interruptions in the growth of the heights of the aromatic‐layer stacks in the crystallites. The optical variations are paralleled by changes in the patterns of the X‐ray lattice parameters for the same samples, which estimate directly the aromatic‐layer diameters (La), the average number of aromatic layers in the stacks (Lc) and the average spacing of the aromatic layers (d). Although the trends followed by the optical properties of the carbonized products of the bitumens and pyrobitumens are generally similar, in detail they show variations that can be related to the initial character of the fresh materials. The carbonization process, as it affects bitumens and pyrobitumens, is briefly discussed in the light of these results.
Reflection Measurements Used In The Analysis Of Structural Colours Of Beetles
Authors: Mossakowski Dietrich 
Published: August 2011

SUMMARYReflectance measurements have been carried out on the elytral cuticle of two beetles. Great differences arise in the tiger beetle Cicindela campestris depending on the extremely structured surface and colour variation from point to point. In comparison the buprestid beetle Chrysochroa vittata appears more even. Indeed macroscopically it looks completely smooth, but there are microscopical structures complicating reflection measurements.The advantages and disadvantages of working with a macro‐ and a microspectrophotometer are listed. The structural properties of the colour producing multilayer system are the same in both species. Measured spectral reflectance curves show the typical form of interference colours. A second order reflectance maximum in the UV region was found.Calculations of the reflectance curves were done by the equations given by Huxley for the non‐ideal type of multilayer reflectors.
Microphotometric Techniques In Intravital Microcirculatory Studies
Authors: Witte Siegfried 
Published: August 2011

SUMMARYIntravital microscopic techniques were developed in order to measure plasma proteins: (1) circulating in the streaming blood of microcirculatory vessels of the exposed rat mesentery, (2) permeating the vessel wall, and (3) moving through the perivascular interstitial tissue. By means of the ultramicrospectrophotometry, the absorbance of proteins containing aromatic amino acids at 280 nm is measured. Absolute amounts of proteins in the range of picograms are measured in a circular measuring field with a diameter of 17 μm. Problems of calibration and of un‐specific light scattering are discussed.The scanning microfluorometry makes use of the fluorescent labelling of the plasma proteins. Interstitial tissue with a capillary vessel containing labelled proteins is measured at high speed. A motor‐driven object stage synchronized with a measuring system uses scanning lines to traverse the tissue. The data are then processed by a computer. In this way we get continuous quantitative information about the dynamics of protein permeability, starting from time zero.The measuring of the fluorescence intensity and the speed of the fluorometric system are further improved by a computerized 10 kHz scanning device.
Electron Microscope Stage Design And Applications
Authors: Valdrè U. 
Published: August 2011

SUMMARYThere is plenty of evidence that future developments in electron microscopy instrumentation will be strongly orientated towards in situ experimental versatility and multisignal exploitation. Based on this assertion, a layout is presented of the achievements in specimen chambers and stages, in attachments for analysis and non‐conventional imaging, and in miscellaneous accessories. Their compatibility and best location is discussed, and general considerations are made on stage design. An example is given of a multipurpose specimen chamber and of a multifunction electron microscope, together with some results of their application for the characterization of semiconductor devices.
Projection Microradiography
Authors: Sharpe R. S. 
Published: August 2011

SUMMARYA considerable amount of additional fine microstructural detail is latently available in radiographs but high resolution techniques are necessary to derive the information in a useful form. This paper explains how the research and enthusiasm of Cosslett and his team (notably Nixon) at the Cavendish Laboratory around the early 1950s resulted in the first practical projection microradiographic system. This not only opened up the possibility of extreme resolution of radiographic detail (down to 0·1 μm) but triggered off a sequence of events that has ensured that high definition radiographic techniques are now an accepted technique for both biological and medical research and routine industrial diagnostics.
The Melbourne proton microprobe
Authors: Legge G. J. F. , McKenzie C. D. , Mazzolini A. P. 
Published: August 2011

SUMMARYA scanning proton microprobe is described which operates in ultra‐high vacuum with a resolution of 10 μm. The operating principles and main features of the design are discussed and the ability of such an instrument to detect trace elements down to a few parts per million by mass is illustrated.
Effect of sodium azide on the ultrastructural preservation of tissues
Authors: Minassian Hassmig , Huang Shao‐nan 
Published: August 2011

SUMMARYAn electron microscopic study was carried out to examine the quality of ultra‐structural preservation of parenchymatous and mesenchymatous tissues and isolated cells fixed in glutaraldehyde with sodium azide (NaN3) as an additive.The dense tissues fixed with conventional glutaraldehyde containing calcium chloride demonstrated only a narrow zone of good tissue preservation on the surface of the specimens. Addition of azide at a concentration of 0·1% greatly improved the cellular preservation in the deeper region of tissues, in particular with respect to the mitochondrial morphology. There was no adverse effect on other cell organelles. The improvement in mitochondrial preservation and the enhancement of penetration of the fixative is presumably due to selective and instantaneous inhibition of mitochondrial metabolic activity by the azide, thus retarding anoxic degenerative effects on cellular structures until permanent fixation is completed by the comparatively slow‐acting aldehyde. However, the addition of azide offers no significant improvement in the ultrastructural preservation of isolated lymphocytes and liver cells, or fibroblasts maintained in culture.
Combined autoradiography and histochemistry: the simultaneous detection of 6‐3H thymidine and acid phosphatase activity in cryostat sections
Authors: Lewis G. H. J. , Bowen I. D. , Bellamy D. 
Published: August 2011

SUMMARYA method is described for the simultaneous demonstration of 6‐3H thymidine incorporation and acid phosphatase activity in cryostat sections of mouse thymus. The method enables a comparison of mitosis and acid hydrolase activity to be made in the same tissue section. In 8‐week‐old mice acid phosphatase positive cells represent 1·23 ±0·06% of the total population and 8·4 ± 0·27% of the cells incorporate tritiated thymidine. Acid phosphatase activity can be used to estimate cell autolysis and death. The implications of the method in relation to tissue dynamics is discussed.
Negative staining‐carbon replica method, a new procedure to reveal ultrastructure of freeze‐fractured membrane
Authors: Fujikawa Seizo 
Published: August 2011

SUMMARYThe present study was undertaken to report a new method which reveals the ultrastructure of freeze‐fractured membrane faces. The method consists of initial replication of fractured surfaces of frozen specimens with evaporated carbon and treatment of the replicas with a negative staining solution after dissolution of specimens. This negative staining‐carbon replica method reveals clear distribution, ultrastructures and precise size of intramembrane particles on the fractured membrane faces by means of density difference of negative staining solution which is deposited on the surfaces of carbon replicas.
Irradiation effects in the electron microprobe quantitation of mineralized tissues
Authors: Edie John W. , Glick Paul L. 
Published: August 2011

SUMMARYThe accuracy of absolute quantitation within thick, mineralized tissue specimens is influenced by count rate variations of characteristic X‐rays during electron microprobe analysis. The variations occur for electron doses 10−10 C/μm2 and are primarily dependent upon the light element fraction within the irradiated volume. Specimen preparation procedures affect both count rate dynamics and interpretation of microanalytical results. X‐ray intensity data acquired at initial electron exposure and utilized in standard matrix correction schemes will project valid elemental concentrations for known calcium compounds over wide ranges of specimen density. Measurement error could approach ±2–3% for the major elemental constituents in mineralized tissues, but only with appropriate control or interpretation of electron irradiation phenomena.
Evaluation of IgG molecules, Fab' fragments and IgG‐horseradish peroxidase conjugates as surface labels for freeze‐etched membranes
Authors: Carter David P. , Staehelin L. Andrew 
Published: August 2011

SUMMARYSheep red blood cell (SRBC) ghosts were incubated with preparations of anti‐SRBC IgG, antigen‐binding fragments of IgG (Fab') or IgG coupled to horseradish peroxidase (HRPO). Frozen samples of the labelled ghosts were deep‐etched and replicated with platinum‐carbon to visualize their surface features in the transmission electron microscope. The surfaces of control ghosts contain a very low number of ‘background’ particles (42 ± 8 particles/μm2) that vary in size from 4·5 to 25 nm. After labelling with whole IgG the density of surface particles (average diameter 12–3 nm) increases dramatically to 480 ± 54 per μm2. Fab'‐labelled ghosts exhibited both significantly fewer (87 ± 14 particles/μm2) and smaller (average diameter 9·8 nm) surface particles. Ghosts labelled with IgG‐HRPO conjugates possessed 590 ± 45 particles/μm2 with an average diameter of 15·3 nm. When these ghosts were incubated with diaminobenzidine and hydrogen peroxide the average size but not the density of the particles increased. Based on these and other observations we conclude that an organic surface marker for freeze‐etched membranes has to have a diameter of > 15 nm if it is to be consistently seen over extended areas and against the background granularity of the surface of a red blood cell ghost. Somewhat better resolution may be expected if markers consisting of inorganic crystals with a distinct shape and coupled to Fab' fragments can be made.
Application of differential interference contrast with inverted microscopes to the in vitro perfused nephron
Authors: Horster Michael , Gundlach Heinz 
Published: August 2011

SUMMARYThe study of in vitro perfused individual nephron segments requires a microscope which provides: (1) easy access to the specimen for measurement of cellular solute flux and voltage; (2) an image with high resolution and contrast; (3) optical sectioning of the object at different levels; and (4) rapid recording of the morphological phenomena. This paper describes an example of commercially available apparatus meeting the above requirements, and illustrates its efficiency.The microscope is of the inverted type (Zeiss IM 35) equipped with differential‐interference‐contrast (DIC) with a long working distance, and an automatically controlled camera system. The microscopic image exhibits cellular and intercellular details in the unstained transporting mammalian nephron segments despite their tubular structure and great thickness and makes obvious function‐structure correlations (e.g. cell volume changes); luminal and contraluminal cell borders are well resolved for controlled microelectrode impalement.
On defining the thermal history of cells during the freezing of biological materials
Authors: Bald W. B. , Crowley A. B. 
Published: August 2011

SUMMARYAn explicit numerical finite difference scheme for defining the thermal history of a cell or group of cells contained within a biological sample of prescribed shape is described. Solutions are presented for three different cases of freezing of biological materials prior to microscopic examination.It is concluded that a surface boundary condition must be specified in any experiment before cell ultrastructure or viability can be related to thermal history or cooling rate.
A new light microscopic method for the synchronous bidirectional illumination and viewing of living cells in different contrast modes, and/or at different focal levels or magnifications
Authors: Malý M. , Vesely P. 
Published: August 2011

SUMMARYA new method of light microscopy for the analysis of the behaviour of living cells in vitro exploits two objects for simultaneous image formation, each serving the other as a condenser. Simultaneous viewing from opposite sides allows the specimen to be examined at: (a) two different magnifications, permitting the locomotion of whole cell (groups) to be studied at a low magnification and details of interaction of colliding surfaces at a high magnification; (b) two different focal levels, permitting, for example, details near the substrate surface to be recorded at the same time as information concerning the behaviour of the free, dorsal surface; and (c) two different contrast modes, such as negative and positive phase contrast, and dark and bright field illuminations.These possibilities can be combined, for example, to contrast a high magnification view in negative phase contrast at one focal level with a low magnification image in ordinary brightfield at another focal level in the same living cells.
How effective is ‘high‐speed’ autoradiography?
Authors: Woodcock C. L. F. , D'Amico‐Martel A. , McInnis C. J. , Annunziato A. T. 
Published: August 2011

SUMMARYA number of methods have recently been described for enhancing silver grain production in light microscope autoradiography by impregnating the emulsion with a 2,5‐diphenyloxazole‐based fluor system. After extensive testing of these methods it was found that none gave a significant increase in silver grain count. In the course of this work a number of observations were made which seem to account at least partially for these failures, and which question the feasibility of this type of fluorography.

Tetrahymena nuclei, pulse labelled with 3H‐thymidine, contain sufficient radioactivity to produce useful autoradiographs after 2 h exposure without fluorographic enhancement.
Although fluorographic autoradiography of this type requires that the fluor penetrate the photographic emulsion, direct evidence was obtained that such penetration does not occur. Thus it is unlikely that true fluorographic enhancement occurs with methods based on 2,5‐diphenyloxazole impregnation of the emulsion. (This is in contrast to the widely used gel fluorography techniques in which it is the gel rather than the photographic emulsion which is impregnated with fluor.)
In DNA fibre autoradiography, it is possible to obtain artefactual arrays of silver grains which closely resemble those expected of replicating DNA. This phenomenon alone, however, does not explain a recent report of successful DNA fibre autoradiography after an exposure of only 3 days. Calculations based on the maximum dpm per length of labelled DNA raise further questions concerning this result.
The Structure And Electrical Properties Of Dislocations In Semiconductors
Authors: Hirsch P. B. 
Published: August 2011

SUMMARYEvidence from weak beam electron microscopy shows that dislocations introduced by deformation of crystals of tetrahedrally coordinated semi‐conductors are dissociated into partials, and suggests that these lie on the‘glide’ rather than the‘shuffle’ planes. Models of the structures of the cores of such partials are described, and it is proposed that the bonds in the cores of the 30° and 90° partials constituting screw and 60° dislocations are reconstructed, forming one dimensional super‐lattices, and that dangling bonds occur only at kinks, antiphase defects, and possibly in the cores of 60° partials constituting edge dislocations. The implications regarding electronic and optical properties are discussed briefly. Consideration of the charge carried by dislocations suggests that significant Coulomb forces between partials may arise only when Cottrell atmospheres of charged point defects or impurities are present.
Tem Of Dislocations Under High Stress In Germanium And Doped Silicon
Authors: Alexander H. , Eppenstein H. , Gottschalk H. , Wendler S. 
Published: August 2011

SUMMARYThe stacking fault energies y of silicon (58 ± 6 mJ m−2) and germanium (75 ± 10 mJ m−2) were determined. Within the limits of accuracy γ was not found to change on doping with (13·8 mol m−3 (8 × 1018 cm−3) boron, and 1·17 mol m−3 (7 × 1017 cm−3) phosphorus). Freezing in dislocations under high shear stress reveals a different behaviour of screw dislocations: whereas these dislocations become wider in pure and p‐silicon, they become narrower in n‐silicon. From this we conclude the ratio of mobilities of the two 30° partials to be different in n‐ and p‐silicon. Other observations on frozen dislocations are mentioned.
Electron Microscope Studies Of Ion Implanted Silicon And Gallium Arsenide After Laser And Furnace Annealing
Authors: Sadana D. K. , Wilson M. C. , Booker G. R. 
Published: August 2011

SUMMARYIn the present investigation, three separate projects are described. First, P+ implanted Si is laser and furnace annealed, and the resulting structures as observed by TEM are compared. Second, similar studies are made of Zn+ implanted GaAs, the laser annealing being performed either with or without a surface encapsulating layer. Third, As+ implanted Si is laser annealed, and the uniformity of the annealing process as determined by SEM EBIC studies is assessed. The results have shown that different damage structures can be produced by laser annealing compared to furnace annealing, and by different laser energy densities. For the laser annealed specimens, the TEM observations provided evidence for the formation of a molten surface layer. The results demonstrated for GaAs that encapsulation was still required for laser annealing, and for Si that laser annealing can give a varying p‐n junction depth within individual slices. The latter is explained by a molten surface layer extending to different depths during the annealing process, this being attributed to spatial variations in laser intensity across the area illuminated.
Surface Structure Studies Of Electron Beam Annealed Ion Implanted Silicon
Authors: Mcmahon R. A. , Ahmed H. 
Published: August 2011

SUMMARYA method of annealing ion implanted silicon with a scanned electron beam is described. Annealing can be achieved without visible damage to silicon or silicon oxide in resistor structures. At excessively high powers, uncontrolled melting can be seen. The structure of the implanted surface layer is shown with SED to change from amorphous to single crystal after annealing.