bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of parallel EEL spectral imaging and elemental mapping in the rapid assessment of anti‐cancer drug localization
Authors: Huxham I. M. , Gaze M. N. , Workman P. , Mairs R. J. 
Published: August 2011

SUMMARYBoth electron spectroscopic imaging (ESI) and electron energy‐loss spectroscopy (EELS) have great potential for use in several areas of cancer research. In biologically targeted radiotherapy, cytotoxic drug therapy and boron neutron capture therapy the effectiveness of many drugs is often critically dependent upon the intracellular localization of the agent employed. We describe the use of parallel EEL spectral imaging to assess the penetration and location of the iodine‐containing drug meta‐iodobenzyl guanidine, of potential value in targeted radiotherapy, and for the rapid detection of boron within borate‐adsorbed polystyrene beads, of potential value in boron neutron capture therapy. We also describe elemental mapping of boron following low‐temperature embedding. These results show how the techniques could be applied to many forms of cancer research by discussing the validity and limitations of the techniques experimentally. We also provide an outline of other areas in this field which could benefit from the future application of ESI and EELS.
Estimation of length density Lv from vertical slices of unknown thickness
Authors: Gokhale Arun M. 
Published: August 2011

SUMMARYLength density of lineal features, Lv, is an important stereological parameter. The efficient stereological procedure for the estimation of Lv from the counting measurement performed on the projected images of the vertical slices (foils) is modified and improved: Lv can be now estimated from vertical slices of unknown thickness, and the slices need not be of the same thickness. The required assumption‐free stereological relationship is
image
is the average number of intersections of straight test lines parallel to the vertical axis with the projected images of the lineal features in the vertical slices, per unit test line length. is the average number of intersections of the lineal features with the parallel planes of the vertical slices, per unit area. Note that there are two parallel planes in a slice, and therefore their total area is twice the area of the observed projected image frame. is the average number of intersections of orientated cycloid‐shaped test lines (minor axis perpendicular to vertical axis) with the projected images of the lineal features in the vertical slices, per unit length. For practical applications of this result, it is necessary uniquely to identify the points of intersections of the lineal features with the parallel planes of the slices in the projected images, so that can be estimated unambiguously. However, in practice, this is not a problem in biological, as well as materials microstructures.
A fast multi‐level decomposition algorithm for n‐dimensional discrete Gabor transforms
Authors: Zhu Zhi Yuan , Barba Joseph 
Published: August 2011

SUMMARYRecently, joint spatial and spatial‐frequency representations have been used in signal processing of non‐stationary signals due to their natural local property and high joint resolution in both the spatial and spatial‐frequency domain. However, a major obstacle to their implementation is their large computation requirements. This paper presents a fast n‐dimensional Gabor transform and signal reconstruction algorithm employing multi‐level parallel decomposition and fast Fourier transform techniques. The algorithm structure lends itself to implementation using VLSI/ASIC technology. Examples of two‐dimensional Gabor transform and reconstruction performed on a AT computer demonstrate the substantial computational saving that can be achieved using the fast Gabor transform.
High‐conductivity amorphous TiSi substrates for low‐temperature electron microscopy
Authors: Rader R. S. , Lamvik M. K. 
Published: August 2011

SUMMARYTo avoid problems with electrostatic charging, electrically conductive specimen support films or coatings must be used when observing non‐conductive organic specimens by electron microscopy. At room temperature, microscopists typically use either carbon films or carbon‐coated plastic films as specimen substrates. Such films have also been adopted for low‐temperature microscopy. Recent measurements have shown that conventional carbon films have high electrical resistivity at low temperature. Thin titanium films have been used to provide improved electrical conductivity, but the structure of titanium films is excessively granular for high‐resolution electron microscopy. With the hope of solving both problems, thin films of Ti88Si12 have been produced using a standard evaporation system. The deposited films are amorphous, as shown by electron microscopy, electron diffraction and differential scanning calorimetry. The electrical conductivity of the binary alloy films is nearly as high as that of pure titanium films. Therefore, these films appear to be appropriate substrates for low‐temperature electron microscopy.
Prospects for confocal imaging based on nanosecond fluorescence decay time
Authors: Morgan C. G. , Mitchell A. C. , Murray J. G. 
Published: August 2011

SUMMARYA fluorescence microscope has been developed to give contrast on the basis of fluorescence decay time. Two different detection schemes are used, one based on an imaging single photon detector equipped with an external photon correlator and the other using an RF‐modulated intensified CCD camera. Examples of the new contrast are shown, and the possible routes to development of a confocal version of the microscope are discussed.
An FFT‐based method for attenuation correction in fluorescence confocal microscopy
Authors: ROERDINK J. B. T. M. , BAKKER M. 
Published: August 2011

SUMMARYA problem in three‐dimensional imaging using a confocal scanning laser microscope (CSLM) in the (epi)fluorescence mode is the darkening of the deeper layers due to absorption and scattering of both the excitation and the fluorescence light. A new method is proposed to correct for these effects. The approach, valid for weak attenuation, consists of multiplying the measured fluorescence intensity by a correction factor involving a convolution integral of the measured signal, which can be computed efficiently by the fast Fourier transform. Analytical and numerical estimates are given for the degree of attenuation under which the method is valid, and the method is applied to various test images. A real CSLM image is restored. Finally, the method is compared with a recent iterative method with regard to numerical accuracy and computational efficiency.
A method to extend the application of microdroplet techniques in the SEM
Authors: CASSID M. F. , ALLEN D. E. 
Published: August 2011

SummaryA thin‐film method of microdroplet analysis is described. The method differs from those published previously. First, uniformly distributed amorphous deposits of chemicals were obtained through the use of a non‐aqueous anti‐crystallization agent, ethylene glycol, which has not been described previously. Second, films of celloidin were used; these could be prepared routinely at 60–80 nm and contained no interfering elements. Initially, these films were too unstable to be of use, but heating them at 60°C greatly improved their stability. A nebulizer was used to deliver microdroplets to these supports, which were, in turn, supported by a specially constructed carbon holder. Minimum detectable concentrations were improved with this method.
Estimation of gold‐labelled macromolecules attached to cell surfaces
Authors: THOMAS N. , GWYNN I. AP 
Published: August 2011

SummaryA method for obtaining a semi‐quantitative estimation of the amount of colloidal gold label attached to a cell surface is described. The X‐ray emission, in a scanning electron microscope, from an even metal coating applied by diode sputter coating is used as an internal standard. The emission from the standard is used to correct for errors which would have arisen due to factors such as variable specimen surface topography. Examples of the semiquantitative estimation of 10‐nm gold‐labelled wheat‐germ agglutinin to L929 murine fibroblast cells are given.
Standards for quantification of elements in the otolithic membrane by electron probe X‐ray microanalysis: Calibration curves and electron beam sensitivity
Authors: LÓPEZ‐ESCÁMEZ J. A. , CRESPO P. V. , CAÑIZARES F. J. , CAMPOS A. 
Published: August 2011

SummaryAn absolute quantitative standardization technique has been developed to measure Ca and K weight fractions (WF) in the otolithic membrane of the saccule and utricle by scanning electron microscopy and electron probe X‐ray analysis using the peak‐to‐background (P/B) ratio method. Microcrystalline salt standards were used to calibrate Ca and K Kα P/B or Y = (P/B) · Z2/A (Z = atomic number; A = atomic weight) against WF at 10, 15, 20 and 25 kV accelerating voltage. The effect of voltage on the calibration, plotting the coefficient of correlation (r) as a function of voltage, was not dependent on the voltage in the range 10–25 kV for Ca standards. K standards were also independent when P/B was corrected for Z2/A. Background counts in the otoconia (Bo) were obtained at 5, 25, 50, 100, 200 and 500 s and used to test the electron beam sensitivity of saccular and utricular otoconia. Bo was not dependent on the spectra acquisition time, with the exception of Bo under Kα K peak in the saccule at 10 kV. Ca and K WF were determined at 10, 15, 20 and 25 kV in the saccule and utricle, showing similar values regardless of the voltage used. This method of calibration offers several advantages, such as stability, homogeneity, known composition of the standards, high reproducibility at different voltages even without Z2/A correction and the similarity between the otoconia and crystal standards. We recommend the application of this method for other elements and biomineral systems.
A portable cryo‐storage system for low‐temperature scanning electron microscopy, suitable for international transport of cryo‐specimens
Authors: JEFFREE C. E. , VAN GARDINGEN P. R. 
Published: August 2011

SummaryA cryo‐specimen storage system for low‐temperature scanning electron microscopy (LTSEM) specimens is described, which: liberates multi‐specimen experiments from sampling restrictions imposed by the rate at which LTSEM specimens can be examined in the SEM; provides security against experiment loss resulting from breakdown of the SEM or cryo‐system; enables collection of specimens in the field or in laboratories remote from the SEM laboratory; and facilitates international air transport of LTSEM specimens. The components of the system, which has a capacity of 98 stub‐mounted specimens, are readily made in a laboratory workshop. The details of the design may be altered to suit particular specimen types or experimental approaches.
A simple filter system for processing small or transparent specimens
Authors: CRIBB B. , ZHU J. 
Published: August 2011

SUMMARYA novel method of attaching a fine mesh filter to the end of a disposable plastic pipette is described. Such a pipette filter can be used to exclude specimen uptake during specimen preparation procedures, particularly when processing small or transparent materials. The pipette filter‐tip does not interfere with fluid exchange and is non‐reactive with normal processing fluids.
Demonstration of aluminium in polyphosphate of Laccaria amethystea (Bolt. ex Hooker) Murr. by means of electron energy‐loss spectroscopy
Authors: KOTTKE I. , MARTIN F. 
Published: August 2011

SummaryToxic aluminium species in acidified soil damage the rootlets of trees. The symbiotic association with ectomycorrhizal fungi may, however, protect the rootlets by sequestration of aluminium in polyphosphates. Electron energy‐loss imaging and spectroscopy was used to identify the relative amount of aluminium in the polyphosphate of the mycelium of the ectomycorrhizal fungus Laccaria amethystea. A three‐window method at the L2,3 edge yielded results which were in agreement with the spectra obtained at the aluminium K edge. The aluminium net distribution images were recorded at 85 eV, the backgrounds at 70 eV and 60 eV, setting the energy selecting slit to 5 eV and the beam current to 15 μA. The method can be used to study the sequestration of aluminium in mycelia of ectomycorrhizal fungi under different stress situations.
Fluorescence saturation in confocal microscopy
Authors: VISSCHER K. , BRAKENHOFF G. J. , VISSER T. D. 
Published: August 2011

SummaryThe effects of fluorescence saturation on imaging in confocal microscopy have been studied. To include saturation it was necessary to deviate from the widely assumed linear relationship between the fluorescence and the illumination intensity. The lateral response for a point‐like object, as well as the optical sectioning power, decreases depending on the degree of saturation. For very high illumination intensities the response for a saturated point object approached that of a conventional fluorescence microscope in which the fluorescence was not saturated. The decrease in the axial confocal response has been confirmed qualitatively by experiment.
A comparison of the analysis of the Fresnel contrast in high‐ and low‐resolution images for the characterization of the rigid body displacements at a grain boundary
Authors: STOBBS S. H. , MEDLIN D. L. , MILLS M. J. , STOBBS W. M. 
Published: August 2011

SummaryThe Fresnel contrast in high‐resolution images of the Σ = 3{112} aluminium twin boundary is quantitatively assessed to determine whether the rigid body displacements might be measured. It is demonstrated that the effects of the shears at the boundary preclude this possibility. By comparison, simulations of low‐resolution images of the same boundary show that the Fresnel fringe contrast in this type of image is negligibly affected by the shear displacements as well as being of considerably higher contrast. The reasons why it is thus only the low‐resolution images that can provide high‐resolution data on the displacements are discussed.
Relocation accuracy on HOME computerized microscopes
Authors: TUCKER J. H. , DYE R. , SPREY J. , SOWTER C. , GRAY E. , BRUGAL G. 
Published: August 2011

SummaryA major practical advantage of the HOME (highly optimized microscope environment) computerized microscope is the facility for relocating cells or other microscopic objects. Features can be marked directly on the microscope image using a mouse‐driven cursor, and an interactive finder can then be used to relocate the marked features. Tests on a prototype HOME microscope have shown that positions can be relocated with an accuracy of standard deviation (SD) < 7 μm. The marked features could also be relocated on a second HOME microscope, although with somewhat reduced accuracy (standard deviations of < 17 μm). The system provides a very user‐friendly environment for tasks requiring relocation of microscopic objects.
Nuclear diffuseness as a measure of texture: Definition and application to the computer‐assisted diagnosis of parathyroid adenoma and carcinoma
Authors: EINSTEIN A. J. , BARBA J. , UNGER P. D. , GIL J. 
Published: August 2011

SummaryA measure of texture, the nuclear diffuseness, was formulated for use in biological classification, and specifically to characterize quantitatively chromatin texture. Nuclear diffuseness corresponds to the amount of local intensity variation in the digitized image of a nuclear profile. As a setting in which to test the efficacy of nuclear diffuseness as a diagnostic tool, the identification of parathyroid adenoma and carcinoma was considered. Digitized images of sections of parathyroid chief cell nuclei were obtained from 16 biopsies, and the nuclear diffuseness, as well as other morphometric descriptors, were computed. With just the average nuclear diffuseness and average nuclear profile area, jackknife (leave‐one‐out) classification using an artificial neural network was able to diagnose correctly and unambiguously the condition (normal, parathyroid adenoma, or parathyroid carcinoma) in 15 of 16 cases. In one case, the neural network assigned a higher weight to the correct diagnosis, but was unable to distinguish between normal and adenoma conclusively.
A simple method for overcoming some problems when observing thick reflective biological samples with a confocal scanning laser microscope
Authors: RUMIO C. , MORINI M. , MIANI A. , BARAJON I. , CASTANO P. 
Published: August 2011

SummaryA simple device is described, which allows the range of depth of scanning to be reduced when observing thick reflecting biological samples with a confocal scanning laser microscope (CSLM). Thick histological sections of human skin and rat brain stem were mounted between two coverslips (‘sandwich’ style) and the optical tomography was performed from both sides by turning the ‘sandwich’ upside‐down. The samples were impregnated using standard Golgi–Cox, ‘rapid Golgi’ or other silver methods. The ability to turn the ‘sandwich’ upside‐down is particularly useful when the reflective structure inspected is deep inside the section, i.e. near the lower surface of the specimen, or when it is opaque to the laser beam or excessively reflective.
Microscopy and formation of polymer/metal composites
Authors: VESELY D. , DISLEY P. , PISACKA J. 
Published: August 2011

SummaryA new class of materials, formed by dispersion of low‐melting‐point metal alloys in a polymer matrix, has been studied from the point of view of microstructure, interfacial interaction and mechanical properties. The phases in these composites were formed in the same way as for polymer blends and were thus dependent on viscosity ratio, concentration, surface tension and interfacial interactions.Metal alloys of tin and bismuth (Sn/Bi) were mixed with high‐density polyethylene (HDPE) and polystyrene (PS) at elevated temperatures. Some preliminary investigations of lead and tin (Pb/Sn) alloys blended with HDPE, PS, polypropylene (PP), polyoxymethylene (POM), polyethylene‐terephtalate (PET), polymethylmethacrylate (PMMA), polycarbonate (PC), polyvinylidenefluoride (PVDF) and Polyvinylchloride (PVC) were also undertaken. The composites were characterized by light and electron microscopy, image analysis, electrical conductivity measurements and impact testing.It is shown that the low‐melting‐point metal alloys can be dispersed in polymers to a submicrometre level by blending. The particle size distribution follows an exponential function, which means that very fine as well as large particles are present. The equilibrium between dispersion and coalescence is very rapidly established during mixing. The average particle size can be controlled by the properties of the matrix, concentration of the metal and processing conditions.An investigation of interfaces revealed that in some cases a chemical interaction between the metal and the polymer can occur. This is apparent by observation of degradation, fluorescence and changes in mechanical properties.
Microstructure and evolution of a magnesium lithium aluminosilicate matrix composite
Authors: RUTERANA P. , KERVADEC D. , MAUPAS H. , CHERMANT J. L. 
Published: August 2011

SummaryThe microstructure of a magnesium lithium aluminosilicate glass ceramic composite has been investigated by scanning electron microscopy and analytical transmission electron microscopy. Attention was focused on the as‐received material, showing that there is a non‐uniform distribution of the major silicate phases inside the matrix. The largest part is made of spodumene‐type crystals containing more than 4wt% Mg. A minor part of the matrix is made of micrometre‐sized crystallites of spodumene and cordierite. The spodumene is always sensitive to the electron beam irradiation. The morphology of the amorphized spodumene areas indicates that it may have crystallized during a later stage of the matrix formation, filling the gaps between cordierite crystallites. The third component of the matrix is made of carbon‐rich areas. They can be as large as 10 μm and they always include amorphous Mg‐rich silicates. However, they are mainly small (a few tens of nanometres in width) when located at grain boundaries of spodumene crystals. In this case the turbostratic carbon patches are also intimately mixed with an Mg‐rich amorphous silicate. The interface between the matrix and the fibres has also been analysed, its thickness changes from one to the other, and it is sometimes empty due to decohesion. When it is filled, its outer part contains mainly tubostratic carbon and the inner part is a mixture of silicon oxide and probably carbon. After creep at 1373K, the spodumene‐type crystals are larger and they are no longer sensitive to the electron beam. The cordierite areas appear to shrink and the amorphous patches which were mixed with carbon transform into small crystallites (1–10 μm). The areas next to the fibres are found to extend irregularly into the matrix, probably as a result of a chemical reaction.
Interfacial reactions in PZT/Pd/PZT sandwich structures
Authors: YAO L. G. , BROOK R. J. 
Published: August 2011

SummaryThe interfacial reactions of palladium foil and lead zirconate‐titanate (PZT) were studied using samples with a sandwich structure in the temperature range 1373–1523 K and under conditions where no lead is lost to the environment. The interfacial reactions were analysed using scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction and wavelength‐dispersive X‐ray spectroscopy analysis. The density of the PZT powder phase increased with increasing temperature and, when sintered above 1373 K, reached over 95% of the theoretical density of PZT. The weight loss of pellets was less than 0·8% when sintered below 1523 K. The degree of interfacial reactions became more severe with increasing temperature, as indicated by an expanding reacted region. The reaction at the PZT side of the Pd/PZT interface involved the decomposition of PZT into a monoclinic ZrO2 phase, PbO and a lower x‐value Pb(ZrxTi1_x)O3 composition. Three distinguishable microstructures exist on the Pd side when sintered below 1473 K: a thin layer of PbPd3 phase, a Pd–Pb solid solution zone and an unreacted region. Only the cubic PbPd3 eutectic structure was found when sintered above 1473 K. The oxidation of palladium occurred during interfacial reactions, expedited by increasing temperature and resulting in the formation of the tetragonal PdO phase and the hexagonal PbPdO2 phase. A model for the overall reaction is proposed involving decomposition of the PZT, migration of PbO and diffusion of Pb into Pd foil.
Spray forming of Al/SiC metal matrix composites
Authors: GRANT P. S. , CHANG I. T. H. , CANTOR B. 
Published: August 2011

SummaryThis paper describes the as‐sprayed microstructure of a model Al‐4wt%Cu/SiC particulate (Al4Cu/SiCp) metal matrix composite (MMC) manufactured by spray forming, and the relationship between microstructure and solidification conditions during manufacture.Injection of SiCp into the melt atomization region during the spray forming of Al4Cu results in significant SiCp incorporation into molten droplets during atomization, and relatively little incorporation during flight to the substrate and at deposition. SiCp clustering is evident in the Al4Cu droplets and results in clustering in the as‐sprayed MMC deposit.Matrix dislocation and precipitation microstructures are dependent upon local solidification conditions during spray forming. Increased dislocation density and increased quantity of fine‐scale θ′‐Al2Cu precipitation is found in the α‐Al(Cu) matrix where local deposit cooling rates are high, i.e. in the vicinity of the substrate/deposit interface and when increased spray distances are used in manufacture. Lower dislocation density and increased quantity of grain‐boundary θ‐Al2Cu is found where deposit cooling rates are relatively low, i.e. distant from the substrate/deposit interface and at decreased spray distances. In all cases, dislocation densities are higher in α‐Al(Cu)/SiCp interfacial regions than in the α‐Al(Cu) matrix.There is no evidence of α‐Al(Cu)/SiCp interfacial reaction in the as‐sprayed condition indicating that cooling rates during spray forming are sufficiently rapid to prevent reaction.