bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of primary Raynaud's syndrome with traditional Chinese acupuncture
Authors: APPIAH R. , HILLER S. , CASPARY L. , ALEXANDE K. , CREUTZIG A.
Published: November 2003

Objective. Evaluation of the effects of a standardized acupuncture treatment in primary Raynaud's syndrome.

Design. A controlled randomized prospective study.

Setting. A winter period of 23 weeks, angiological clinic of Hannover Medical School.

Subjects. Thirty‐three patients with primary Raynaud's syndrome (16 control, 17 treatment).

Interventions. The patients of the treatment group were given seven acupuncture treatments during the weeks 10 and 11 of the observation period.

Main outcome measures. All patients kept a diary throughout the entire observation period noting daily frequency, duration and severity of their vasospastic attacks. A local cooling test combined with nailfold capillaroscopy was performed for all patients at baseline (week 1) and in weeks 12 and 23, recording flowstop reactions of the nailfold capillaries.

Results. The treated patients showed a significant decrease in the frequency of attacks from 1.4 day‐1 to 0.6 day‐1, P<0.01 (control 1.6 to 1.2, P=0.08). The overall reduction of attacks was 63% (control 27%, P=0.03). The mean duration of the capillary flowstop reaction decreased from 71 to 24 s (week 1 vs. week 12, P=0.001) and 38 s (week 1 vs. week 23, P=0.02) respectively. In the control group the changes were not significant.

Conclusions. These findings suggest that traditional Chinese acupuncture is a reasonable alternative in treating patients with primary Raynaud's syndrome.
Alcohol and coronary heart disease: the roles of HDL‐cholesterol and smoking
Authors: MÄNTTÄRI M. , TENKANEN L. , ALIKOSKI T. , MANNINEN V.
Published: November 2003

Objectives. To study the role of HDL‐cholesterol (HDLc) in the causal pathway mediating the effect of alcohol on coronary heart disease (CHD).

Design. Cox proportional hazard models were used to compare the relative CHD risks in various HDLc–smoking categories.

Setting. A prospective, multicentre, placebo‐controlled, double‐blind CHD primary prevention trial with gemfibrozil in primary (occupational) health care units, the Helsinki Heart Study.

Subjects. Dyslipidaemic middle‐aged men with available alcohol consumption data (1924 of 2035) in the placebo arm of the 5‐year study.

Main outcome measures. Seventy‐seven (of 84) cases of nonfatal myocardial infarction or cardiac death.

Results. A U‐shaped association was detected between alcohol consumption and CHD. The protection was found both in subjects with low (mean 0.94 mmol L−1) and normal (mean 1.25 mmol L−1) HDLc with corresponding reductions of 23% and 36% in relative risks. In contrast to previous data, alcohol offered virtually no protection against CHD in non‐smokers. In subjects consuming more than 800 g pure ethanol annually, the CHD incidence was 6/1000 in subjects with more than three weekly drinking occasions, compared to 11/1000 in ‘weekend’ drinkers.

Conclusions. Our results confirm the protective effect of alcohol against CHD. However, in contrast to previous data the effect in our population is restricted to smokers and the role of HDLc in mediating the effect is less central than suggested previously.
Centred contact density functions for the statistical analysis of random sets A stereological study on benign and malignant glandular tissue using image analysis
Authors: Mattfeldt T. , Schmidt V. , Reepschläger D. , Rose C. , Frey H.
Published: November 2003

Real structures investigated in the material and biological sciences, such as minerals or tissues, can often be reduced to two phases. In a stochastic approach, the components of such binary structures may be considered as the union of grains — random sets implanted with their centres at random points — and their complementary space, which is called the pore space. The simplest stochastic germ‐grain model is the Boolean model of random sets, which we use here instrumentally as a null model (reference model) for comparison with our biological material. After a brief review of basic properties of the Boolean model and related statistical methods, we introduce centred contact density functions as a new approach. Empirical contact density functions are estimated from the empirical contact distribution functions with an image analyser by dilation of the grain phase. Theoretical contact density functions are then predicted from a set of image parameters, under the assumption that the Boolean model holds. A centred contact density function is the difference between the estimated and the predicted contact density function. Apart from a random error term, centred contact density functions amount to zero irrespective of the area fraction of the grain phase, when the germ‐grain model is Boolean. As a section of a spatial Boolean model is a planar Boolean model, the method is also applicable in stereological studies where digitized images are obtained from sections of a three‐dimensional structure. Centred contact density functions were determined for mastopathic tissue as compared to mammary cancer, and for tumour‐free prostatic tissue as compared to prostatic cancer. For each category of specimens, twenty cases with 10 images each were analysed. Benign and malignant glandular tissue of the aforementioned types deviates significantly from the Boolean model. Centred contact density functions show that malignant transformation is connected with profound geometric remodelling of the pore space.
Analysis of nanometre‐sized pyrogenic particles in the scanning transmission electron microscope
Authors: WALLIS D. J. , Browning N. D. , Megaridis C. M. , Nellist P. D.
Published: November 2003

The chemical reactions that take place at surfaces as well as internally in nanoscale particles are of great scientific interest. Such reactions control the catalytic properties of small metal particles and thus are technologically very important. In order to allow enhancement of the performance of such catalytic systems, an understanding of the processes taking place at the atomic scale is necessary. Z‐contrast imaging and electron energy‐loss spectroscopy (EELS) in the dedicated scanning transmission electron microscope can give atomic‐scale information and thus provide a unique opportunity to study such nanoscale systems. Here, iron particles from known positions in a ferrocene‐seeded flame and their effects on soot formation are studied. Using EELS, spatial variations in oxidation state of the metal atoms are detected across individual nanometre‐sized particles collected from the post‐flame region. The surfaces of these particles are found to be less oxidized than their centres. Additionally, the particles are imaged with atomic resolution allowing their structure to be identified. Using these results and those for particles collected from in‐flame regions, direct evidence is provided for the catalytic role of Fe‐containing particles in the removal of carbonaceous soot produced during combustion of hydrocarbon‐based fuels.
Preparation of ceramic fibre TEM cross‐sections using ultramicrotomy and ion beam thinning methods
Authors: LI R. , WADSWORTH I. , YOUNG J. , Acheson R.
Published: November 2003

The preparation of specimens for detailed TEM microanalysis of micrometre‐diameter, ceramic fibre cross‐sections is described. The starter material is ceramic fibre in powder form and both ultramicrotomy‐based and ion beam thinning‐based methods are described. Requirements for specimens of uniform and adequate thinness, for easy selection of representative fibre cross‐sections within the same specimen and for a reliable and time‐efficient preparation method, resulted in choice of the ultramicrotomy‐based method and the associated development of a novel extrusion and sedimentation technique of embedding the fibres to provide necessary pre‐alignment and packing.
The use of vibratome sections for the ruthenium tetroxide protocol: a key for optimal visualization of epidermal lipid bilayers of the entire human stratum corneum in transmission electron microscopy
Authors: Van Der Meulen J. , Van Den Bergh B. A. I. , Mulder A. A. , Mommaas A. Mieke , Bouwstra J. A. , Koerten H. K.
Published: November 2003

In this paper we describe a preparative procedure which allows maximal visualization of all lipid bilayers in the human stratum corneum (SC). We used 50‐μm‐thick vibratome sections of paraformaldehyde/glutaraldehyde‐fixed human skin. The sections were post‐fixed in 1% osmium tetroxide and 0.5% ruthenium tetroxide. The vibratome sections were dehydrated only in 70% ethanol in order to prevent dissolution of the lipids.  Lipid bilayers, including the alternating electron‐dense and electron‐lucent lamellae, were visible between all cell layers of the SC. In addition, this preparative procedure also appeared to be excellent for the ultrastructural preservation of lamellar bodies.
Fluorescent porphyrin counterstaining of chromatin DNA in conjunction with immunofluorescence methods using FITC‐labelled antibodies
Authors: JUARRANZ A. , VILLANUEVA A. , CAÑETE M. , STOCKERT J. C.
Published: November 2003

This work describes the use of two cationic porphyrins for fluorescent DNA counterstaining of HeLa cells also stained by means of indirect immunofluorescence with fluorescein isothiocyanate (FITC)‐conjugated secondary antibodies. Staining HeLa cells with meso‐tetra(4‐N‐methylpyridyl)porphine (T4MPyP) and meso‐tetra( p‐N‐trimethylanilinium)porphine (TMAP), both used at 5 × 10−6 m, gives rise to a deep red emission of chromatin from interphase nuclei and mitotic chromosomes when the cells are excited with blue (490 nm) light. The red‐fluorescing chromatin contrasted very well with the yellowish‐green emission from FITC‐immunofluorescent staining. No significant difference in chromatin fluorescence found with either T4MPyP or TMAP was detected. Counterstaining with the porphyrins could be carried out as a separate step after immunolabelling or, more simply, by their inclusion in the mounting medium. Spectral analysis demonstrated that the fluorescent emission maximum of T4MPyP was at 665 nm and that the intensity of the fluorescent emission showed a considerable increase in the presence of DNA
Fading and broadening of electron diffraction spot from beam‐damaged multiple monolayer films
Authors: OHNO T.
Published: November 2003

In contrast to the increase in the extinction dose for thick specimens, observed broadening rates of diffraction spots from behenic acid multiple monolayers were independent of specimen thickness. This result leads to the conclusion that specimens are always decaying at the same rate although the periodicity of crystals still remains in thick specimens. The conclusion is interpreted as being the result of the radiation damage mechanism based on longitudinal motions of long chain molecules. For the evaluation of beam damage effect the broadening rate and the extinction dose should be used as indicator for the radiation sensitivity of crystals and for the possibility of observing diffraction patterns, respectively.
On the rose of directions measurements on the discrete grid of an automatic image analyser
Authors: CHAIX J.‐M. , GRILLON F.
Published: November 2003

Estimation of the rose of directions is a simple way to analyse the anisotropy of structures made of lines, objects or interconnected phases. However, when used on an automatic image analyser with a square frame, the rose of directions obtained from circles is not uniform. This problem is analysed here. It originates in the interpretation of the discrete rose of directions, which is not a histogram, but an averaging with non‐constant angular mask and weight function. New coefficients are proposed to get a pseudo‐rose of directions which is uniform for isotropic structures such as assemblies of circles.
Soft‐X‐ray damage to biological samples
Authors: FUJISAKI H. , TAKAHASHI S. , OHZEKI H. , SUGISAKI K. , KONDO H. , NAGATA H. , KATO H. , ISHIWATA S.
Published: November 2003

X‐ray damage to biological samples was investigated in the wavelength region of 2.7–5 nm, which overlaps the so‐called ‘water window’, the wavelength range of 2.4–4.3 nm usually used in X‐ray microscopy. Yeast cells and myofibrils were chosen as representatives of whole cell samples and motile protein systems, respectively. The samples were exposed to X‐rays using an apparatus composed mainly of a laser‐plasma X‐ray source, a Wolter mirror condenser, and a sample cell. The yeast cells lost their dye exclusion ability when the X‐ray flux was higher than 1 × 106 photons μm−2, while the myofibrils lost contractility when the X‐ray flux was higher than 4 × 105 photons μm−2. These X‐ray fluxes are lower than the flux required for the X‐ray microscope observation of biological samples at a resolution higher than that of light microscopes.
Fourier transform multipixel spectroscopy for quantitative cytology
Authors: MALIK Z. , CABIB D. , BUCKWALD R. A. , TALMI A. , GARINI Y. , LIPSON S. G.
Published: November 2003

A Fourier transform multipixel spectroscopy system was set up and applied to fluorescence microscopy of single living cells. Continuous fluorescence spectra for all pixels of the cell image were recorded simultaneously by the system. Multiple frames of data were first acquired and stored as a set of interferograms for each pixel of the image; they were then Fourier transformed and used as a spatially organized set of fluorescence spectra. Practical spectral resolution of 5 nm was achieved, typically, for 104 pixels in a single cell. The net result was I(xy,λ), the fluorescence intensity (I) for each pixel of the image (xy), as function of wavelength (λ). The present study demonstrates that multipixel spectroscopy can reveal dynamic processes of the food‐digestive cycle in the unicellular Paramecium vulgaris fed with algae. Spectral variability of fluorescence intensity at different cytoplasmic sites pinpointed the location of cellular deposits of chlorophyll (630 nm) and of pheophytin (695 nm), a digestive product of the chlorophyll. Localization of compartmental spectral changes was achieved using a ‘similarity mapping’ algorithm, followed by enhanced image construction. Similarity mapping based on the fluorescence spectrum of native chlorophyll revealed a highlighted image of the cell cytopharynx structure where algae were ingested. Phagolysosomes, migrating vacuoles and the cytoproct, each containing different ratios of pheophytin, were similarly imaged.
Electron holographic observation for biological specimens: electron holography of bio‐specimens
Authors: AOYAMA K. , RU Q.
Published: November 2003

Electron holography has been applied to the observation of biological filaments. The technique has some advantages over conventional imaging for observing weak‐phase objects such as small unstained biological structures. To avoid artificial structural transformation of the sample owing to the interaction with the supporting film, a holey carbon film was used to support the filaments. A tobacco mosaic virus bridged over a hole was observed as a cylindrical shape; the contrast distribution across the filament represents its actual shape, which is difficult to obtain with conventional transmission electron microscopy. A number of technical limitations which at present prevent high‐resolution structure analysis of biological macromolecules by electron holography are discussed in this report.
Energy‐filtering TEM and electron energy‐loss spectroscopy of double structure tabular microcrystals of silver halide emulsions
Authors: R.  , JACOB W.
Published: November 2003

Composite Ag(Br,I) tabular microcrystals of photographic emulsions were studied by the combination of energy‐filtering electron microscopy (EFTEM) and electron energy‐loss spectroscopy (EELS) in conjunction with energy‐dispersive X‐ray (EDX) microanalysis. The contrast tuning under the energy‐filtering in the low‐loss region was used to observe more clearly edge and random dislocations, {11−1} stacking faults in the grain shells parallel to {11−2} edges and bend and edge contours. Electron spectroscopic diffraction patterns revealed numerous extra reflections at commensurate positions in between the Bragg reflections and diffuse honeycomb contours; these were assigned to the number of defects in the shell region parallel to the grain edges and polyhedral clusters of interstitial silver cations, respectively. Inner‐shell excitation bands of silver halide were detected and confirmed by EDX analyses, i.e. the Ag N2,3 edge at 62 eV (probably overlapped with the weak I N4,5 edge at 52 eV and the Br M4,5 edge at 70 eV), the I M4,5 edge at about 620 eV, and the Br L2,3 edge at about 1550 eV energy losses. Energy‐loss near‐edge structure of the Ag M4,5 edge at about 367 eV energy losses and low‐loss fine structure arisen as a result of interband transitions and excitons, possibly superimposed with many electron effects, have been revealed. The crystal thickness was determined by a modified EELS log‐ratio technique in satisfactory agreement with measurements on grain replicas.
Phase identification in composite materials by EELS fine‐structure analysis
Authors: SCHNEIDER R. , WOLTERSDORF J. , LICHTENBERGER O.
Published: November 2003

Microanalytical results obtained from two SiC‐fibre‐reinforced borosilicate glasses with hot‐pressing temperatures of about 1373 and 1543 K show that for nanometre‐sized regions a detailed phase analysis with respect to the chemical bonding of a certain element is possible by investigating energy‐loss near‐edge structures (ELNES). Examples are presented of the bonding state of silicon as revealed by analysing the Si‐L23 ELNES, which generally varies from predominantly carbidic in the fibre to oxidic in the matrix. In addition, content and type of silicon‐containing phases inside carbon‐rich interlayers, usually arising between fibre and matrix owing to chemical reactions, are characterized.
Diffraction effects in inner‐shell ionization edges
Authors: Schattschneider P. , Nelhiebel M. , Schenner M. , GROGGER W. , HOFER F.
Published: November 2003

The influences of elastic on inelastic scattering under systematic‐row conditions are described in a simple way. A kinematic approach, superposing inelastic intensity‐distribution profiles centred at different Bragg spots is shown to be qualitatively correct but quantitatively unsatisfying. A model considering Bragg reflection of the fast electron before and after the inelastic scattering process and thus introducing interference effects is in good agreement with experimental results. Experimentally, we recorded inelastic intensities in the diffraction pattern of an epitaxial copper foil using a PEELS spectrometer and observed energy filtered extinction contours of a copper crystal.
Stereological analysis of the layered collagen of human intracranial aneurysms
Authors: CANHAM P. B. , FINLAY H. M. , TONG S. Y.
Published: November 2003

Intracranial saccular aneurysms are balloon‐like distensions of the arterial wall; they increase in size gradually, a few to the point of bleeding or catastrophic rupture. Collagen is the primary structural component of the aneurysmal wall, and because only a small fraction of aneurysms fail, the collagen fabric must effectively reorganize in order to maintain mechanical integrity as an aneurysm changes size. Data were obtained from four human aneurysms, fixed at 110 mmHg of distending pressure with 10% buffered formalin, and sectioned completely through at 4 μm thickness. Each set of measurements included groups of data taken layer by layer from a radial corridor across the aneurysm wall. Each three‐dimensional orientation measurement, for which we used a Zeiss polarizing microscope with a universal stage attachment, is defined by an azimuth and elevation angle relative to the section plane. We compared the interdependence of these measured angles with a mathematical model based on fibres following great circle trajectories, and related the measured azimuth and elevation angles to the relative depth of the section into the aneurysm. Data were plotted on Lambert equal‐area projections, along with the theoretical relation between azimuth and elevation, that included wall thickness and depth of sectioning. The graphical relationship between measured azimuth and elevation for collagen fibres across the layered fabric of the aneurysmal wall is consistent with the theoretical great circle trajectories for collagen fibre alignment. Analysis was based on statistics for spherical data to give values for the mean orientation and the circular standard deviations (CSD) about that mean. The results indicate that any given region on the aneurysm wall is made up of many, very thin sublayers, most of which have a relatively coherent organization (mean CSD 8°). These measurements agree well with the mathematical model and, when considered collectively, the layers provide a balanced distribution for bearing the biaxial tensile stress of the wall.
Quantitative X‐ray imaging of labelled molecules in tissues and cells
Authors: KIRK R. G. , GATES M. E. , CHANG CHUN‐SHIA , LEE P.
Published: November 2003

Using cisplatin as a model system, we have been able to demonstrate the feasibility of studying the cellular and subcellular distribution of a labelled molecule containing a single atom of platinum per molecule in bone marrow. An X‐ray imaging system consisting of a microcomputer, a 4pi system and a software package was interfaced with an electron microscope enabling the computer to control the beam movements as well as receive signals from the STEM and EDS X‐ray detectors. X‐ray imaging is useful for both tissue and samples in which the population of cells is not homogeneous. Imaging permits elemental distributions to be measured throughout the sample and not in just randomly selected areas as previously done in X‐ray microanalysis. Images are created for not only the element labelling the molecule of interest but also other specified elements present.

Three types of maps for imaging labelled molecules are compared and discussed. When the original (collected) data are mapped, the elements of interest are obscured by the continuum. The maps calculated using an internal standard give a concentration distribution on the basis of volume (mmol L−1 of packed cells). The maps calculated using the continuum normalization method according to Hall produces concentration distribution on the basis of mass (mmol kg−1 dry weight). By recalculating using the ‘Peak’ or ‘Hall’ method the continuum problem is removed yielding quantitative images of the intracellular distribution of labelled molecules present in low concentrations.
Real‐time two‐photon confocal microscopy using a femtosecond, amplified Ti:sapphire system
Authors: BRAKENHOFF G. J. , SQUIER J. , NORRIS T. , BLITON A. C. , WADE M. H. , ATHEY B.
Published: November 2003

The bilateral imaging approach known from confocal applications operating in the line mode was used to realize real‐time two‐photon imaging. It is shown that the sectioning inherent to two‐photon imaging could be improved by the introduction of a confocal line aperture in the imaging path. Using a high‐power, low‐repetition‐rate amplified Ti:sapphire system, various biological objects were visualized including live boar sperm.
Solvent vapour lock: an extreme case of the problems caused by lignified and suberized cell walls during resin infiltration
Authors: ENGLAND W. E. , McCULLY M. E. , HUANG C. X.
Published: November 2003

To determine the cause of floating tissue pieces and poor resin infiltration, sugarcane stem tissue was monitored during processing for microscopy. Bubbles formed within cells at the early stages of solvent replacement (the timing dependent on the fixation used), and increased in volume to fill the cells as resin concentration increased. It is concluded that bubbles form by solvent cavitation (formation of a solvent vapour phase) as hydraulic pressure decreases within the cells, because the thick, lignified and suberized walls are freely permeable to the solvent but not to the resin molecules. The pressure difference across the walls that would be required to release the vapour lock cannot be achieved by vacuum infiltration. In more flexible, thinner‐walled, suberized and lignified tissues in maize roots, the lowering of hydrostatic pressure in the cells results in distortion by cytorrhysis (cell collapse). The analogy is drawn between the cavitation and cytorrhysis of cells during resin infiltration and the same processes which occur in living plant cells during water stress. Cavitation and cytorrhysis did not occur in sugarcane or maize tissues processed by anhydrous freeze substitution.
A novel organ bath design enables the use of saline‐immersible lenses on inverted microscopes
Authors: Cody S. H. , Williams D. A.
Published: November 2003

We describe the design of an organ bath that is of great advantage for microscopy of living specimens, during physiological experiments, or when used in conjunction with confocal microscopy where deep optical sectioning of living specimens is a priority. For the first time water‐immersion lenses of the type that may be immersed directly into physiological saline may be used with inverted microscopes. The novel design of the organ bath allows the lens to have direct access to the specimen through a hole in the base of the bath, without requiring a cover‐glass. This method is ideal for experiments in which micropipettes or micromanipulators are in use. The benefit of using saline‐immersible lenses for optically sectioning deep into living specimens is discussed, with comparison to results with the more commonly used dry, long‐working‐distance lenses.
Stereological estimation of mean linear intercept length using the vertical sections and trisector methods
Authors: KARLSSON L. M. , GOKHALE A. M.
Published: November 2003

A method for estimating the mean linear intercept length of anisotropic microstructures using vertical sections is presented. A test system of cycloids and points is overlaid on the vertical sections, and the mean linear intercept length is estimated from a simple counting procedure — no length measurements are required. The vertical direction is either arbitrarily chosen or chosen perpendicular to most of the surface boundaries of the objects of interest. A design with the latter choice of the vertical direction and three vertical sections — a trisector — will optimize the precision of the estimate from only three vertical sections. The method was applied to two metallic structures, but it may also be used in a biomedical context.
Characterization and microanalysis of interfacial reactions in metal–matrix composite systems
Authors: HEFFELFINGER J. R. , KIESCHKE R. R. , CARTER C. B.
Published: November 2003

Understanding the solid‐state reactions involved in metal/ceramic systems is important when combining the two types of materials into a composite. In this investigation, the solid‐state reaction between Al2O3 (alumina) and a β‐Ti alloy has been characterized by transmission electron microscopy (TEM), scanning electron microscopy, parallel‐acquisition electron energy‐loss spectroscopy and X‐ray energy‐dispersive spectroscopy. Two different systems were used to investigate this reaction. The first system utilizes a controlled reaction geometry and involved diffusion bonding single‐crystal α‐alumina and a β‐Ti alloy. Here, three interfacial regions were found to form: a region of intermetallics (Ti3Al and TiAl) located near the alumina interface, an α‐Ti region, and a β‐Ti region (rich in Mo, the β‐phase stabilzer). Analysis of cross‐section TEM samples of this reaction revealed the presence of both Ti3Al and TiAl at the alumina interface. Orientation relationships between the intermetallics and the alumina are discussed. In the second, system, interfacial reactions inside metal–matrix composites that contain alumina and a β‐Ti alloy were investigated. Here, different coatings used in the MMCs are investigated for their ability to prevent the reaction between the matrix and fibres. Reaction products inside the MMCs are compared with those found in the model reaction geometry.
Microstructure and creep characteristics of experimental SiCf–YMAS composites
Authors: VICENS J. , DOREAU F. , CHERMANT J. L.
Published: November 2003

A unidirectional SiCf –YMAS glass–ceramic composite has been developed by Céramiques‐Composites (Bazet) and ONERA (Establishment of Palaiseau) in France. The matrix is totally crystalline and consists essentially of two main phases, cordierite and yttrium disilicate, with some minor phases, mullite, spinel, zirconium and titanium oxides. Image analysis methods have been used to characterize the homogeneity of the composite plates and to obtain granulometric information on the different matrix phases. Different interphase layers formed during the process by reaction between the matrix and the Nicalon NLM 202 fibres have been studied by using HREM and EDX. Their chemical composition has been determined by stepping the probe (8 nm) across the fibre–matrix interface. Two distinct nanoscale sublayers have been imaged. The sublayer on the matrix side has a light contrast in the TEM. The microstructure of this layer (≈ 80 nm) is typical of a turbostratic carbon. The carbon layer also contains Al, O, Mg and Si. The silicon content is low in the carbon layer. The sublayer on the fibre side (≈ 100 nm thick) has a dark contrast in the TEM. Profiles have been taken across this sublayer also. Tensile creep tests in air have been performed to investigate the tensile creep behaviour at 1223 K. They have been conducted in the 50–200 MPa stress range. Tensile creep results indicate that creep rates are of the same order of magnitude as for other glass–ceramic composites. Optical micrographs and SEM observations have revealed the damage in the composite. Changes occurring in the interface region have been studied at a finer scale by TEM and HREM at the surface of the sample and in the core. These observations enable us to explain the mechanical behaviour of the composite observed on a macroscopic scale.
Edge‐corrected estimators of the nearest‐neighbour distance distribution function for three‐dimensional point patterns
Authors: REED M. G. , HOWARD C. V.
Published: November 2003

In multiphase systems consisting of ‘particles’ embedded in a matrix the three‐dimensional spatial distribution of the particles may represent important structural information. In systems where the matrix is transparent or translucent recent developments in microscopy allow the three‐dimensional location of particles to be recorded. Using these data a spatial statistical, or second‐order stereological, analysis can be carried out. In second‐order stereology functions of interparticle distances are used as summary statistics of the spatial distributions. These statistics show whether the particles are randomly arranged or, more commonly, either clustered together or inhibited from close approach to each other. This paper focuses on the estimation of one of these spatial statistics, the nearest‐neighbour distance distribution function or G‐function. In practice, estimation of the G‐function is plagued by an ‘edge‐effect’ bias introduced by the sampling process itself. There exist a number of G‐function estimators that tackle this edge effect problem; for single sample ‘bricks’ it can be shown that these estimators become increasingly accurate as the brick size increases, i.e. they are consistent. However, in many practical cases the size of a sampling brick is fixed by experimental constraints and in these circumstances the only way to increase sample size is to take replicated sampling regions.

In this paper we review a number of existing G‐function estimators and propose a new estimator. These estimators are compared using the criterion of how well they overcome the edge‐effect when they are applied to replicated samples of a fixed size of brick. These comparisons were made using Monte‐Carlo simulation methods; the results show that three existing estimators are clearly unsuitable for estimating the G‐function from replicated sample bricks. Of the other estimators the recommended estimator depends upon the number of replicates taken; however, we conclude that if a total of more than about 800 points are analysed then the bias in the pooled estimate of the G‐function can be reduced to tolerable levels.
Analysis and modelling of tessellations by means of image analysis methods
Authors: Schwertel J. , Stamm H.
Published: November 2003

A QUANTIMET 570 image processing system was used to determine the grain morphology of an austenitic steel. The applied methods can be generalized to other tessellation structures. The grain morphology is studied using plane micrographs where the grain boundaries were made visible by etching. The image processing using grey and binary image transformations, which improve the visibility of the grain boundaries, is described. The resulting plane section cell structure is investigated with respect to different characteristic cell parameters. Basic stereological relationships are used to check the detection. The mean values obtained are compared with the theoretical and simulated values predicted by the Poisson–Voronoi model, the homogeneous Johnson–Mehl model and the ASTM model. It is found that these mean values for the different distributions are in agreement with the theoretical ones for each of the three models. For the Poisson–Voronoi mosaic where the distributions of the measured quantities are also known, the measured distributions are compared with the predicted ones. It is found that significant differences in the shape of the distributions occur.
Structure and morphology of the in situ composites of a liquid crystalline polymer and polycarbonate
Authors: HU X. , LIN Q. , YEE A. F. , LU D.
Published: November 2003

In situ composites were prepared via melt blending of a liquid crystalline polymer (LCP) and polycarbonate using a twin screw extruder. The structure and morphology of these composites were analysed using both transmission electron microscopy (TEM) and scanning electron microscopy. The LCP phases were able to orientate and form in situ submicrometre fibres during the extrusion and post‐extrusion drawing. TEM images as well as selected‐area diffraction patterns were obtained from the materials. The effects of both composition, i.e. LCP content, and post‐extrusion draw‐down ratio on the development of the in situ formed LCP fibres were studied in detail. A skin–core morphological differentiation is observed in these materials where well‐defined LCP fibres of higher aspect ratios were formed in the skin region. However, a significant amount of unelongated LCP particles were found coexisting with the less well‐defined fibres in the core region of the extrudates. This skin–core differentiation was found to be dependent on the composition and the processing conditions, e.g. draw ratio. In this instance, electron microscopy is proven to be a powerful technique not only for direct observation of the formation, dimensions and morphology of the in situ LCP fibres, but also for the qualitative and quantitative characterization of the molecular orientation and crystalline structures in these fibres using selected‐area electron diffraction. It is observed that the skin–core differentiation becomes more distinct in the in situ composites containing a higher percentage of LCP but diminishes when the material is processed at higher post‐extrusion draw ratio.
Three‐dimensional atom probes
Authors: Miller M. K.
Published: November 2003

A three‐dimensional atom probe permits the elemental reconstruction of a small volume of a specimen by determining the x, y and z positions and mass‐to‐charge ratio of the atoms in that volume. The historical development of this new type of atom probe is described. Several variants of these instruments including the position‐sensitive atom probe, the optical atom probe and the tomographic atom probe are reviewed. The various methods of data visualization and analysis are summarized. The performance of the three‐dimensional atom probe is compared with the energy‐compensated atom probe.
Carbon nanotubes and other graphitic structures as contaminants on evaporated carbon films
Authors: HARRIS P. J. F.
Published: November 2003

Evaporated carbon support films for transmission electron microscopy (TEM) often contain fullerene‐like structures such as nanotubes and nanoparticles. This could cause serious confusion in TEM studies of fullerene‐related carbons. Other, poorly graphitized, particles are also frequently seen.
Intermediate aggregates resulting in the interaction of bile salt with liposomes studied by transmission electron microscopy and light scattering techniques
Authors: De La Maza A. , Manich A. M. , Parra J. L.
Published: November 2003

The interaction of sodium cholate (SC) with phosphatidylcholine liposomes was studied by means of transmission electron microscopy (TEM), changes in the mean particle size (quasielastic light scattering, QELS) and in the static light scattering (SLS) of the system during liposome solubilization. A good correlation was found between the TEM diameter of particles and the mean hydrodynamic diameter (HD) determined by QELS. The intermediate aggregates resulting in this interaction were dependent on the SC concentration in the system. Thus, an initial vesicle growth occurred when the SC concentration in the system was 13.79 mol%. Additional SC amounts (41.17 mol% SC) led to the formation of the largest vesicles (HD 410 nm). Increasing SC amounts led to a slight fall in the vesicle diameter and in the SLS of the system. Thus, for 47.08 mol% SC, TEM images still showed the presence of vesicles albeit with traces of smaller structures and signs of vesicle fusion. When SC concentration exceeded 48 mol% an abrupt decrease in SLS occurred, the size curve starting to show a bimodal distribution. Thus, for 50 mol% SC a sharp distribution curve appeared at 52 nm indicating the formation of small particles and TEM images showed clear signs of vesicle disintegration with formation of tubular structures. The subsequent self organization of these tubular structures (54 mol% SC) led to the formation of open multilayered structures in coexistence with small particles. A gradual increase in the number of these small particles (mixed micelles) led to the complete solubilization of liposomes.
Calibration of the automated z‐axis of a microscope using focus functions
Authors: Boddeke F. R. , Van Vliet L. J. , Young I. T.
Published: November 2003

Applications in automated microscopy and three‐dimensional microscopy require careful calibration of the microscope system. This paper presents methods for calibration of the motorized z‐axis (focus or optical axis) of an automated microscope. Apart from the automated microscope the procedures require a CCD camera and a test slide containing a simple bar pattern. The calibration embraces the following characteristics of the z‐axis: (a) measuring the motor step size in nanometres; (b) measuring the mechani‐cal backlash in the focus mechanism of the microscope and (c) measuring the reproducibility and the stability of the focus position over time. The measurements employ focus functions to determine the z‐position of the microscope stage.
Double‐pulse fluorescence lifetime measurements
Authors: Buist A. H. , Müller M. , Gijsbers E. J. , Brakenhoff G. J. , Sosnowski T. S. , Norris T. B. , Squier J.
Published: November 2003

It is demonstrated that fluorescence lifetimes in the nanosecond and picosecond time‐scale range can be observed with the recently proposed double‐pulse fluorescence lifetime imaging technique (Müller et al., 1995, Double‐pulse fluorescence lifetime imaging in confocal microscopy. J. Microsc177, 171–179).

A laser source with an optical parametric amplifier (OPA) system is used to obtain short pulse durations needed for high time resolution, wavelength tunability for selective excitation of specific fluorophores and high pulse energies to obtain (partial) saturation of the optical transition.

It is shown that fluorescence lifetimes can be determined correctly also with nonuniform saturation conditions over the observation area.

A correction scheme for the effect on the measurements of laser power fluctuations, which are inherently present in OPA systems, is presented. Measurements on bulk solutions of Rhodamine B and Rhodamine 6G in different solvents confirm the experimental feasibility of accessing short fluorescence lifetimes with this technique.

Because signal detection does not require fast electronics, the technique can be readily used for fluorescence lifetime imaging in confocal microscopy, especially when using bilateral scanning and cooled CCD detection.
Estimation of the section thickness and optical disector height with a simple calibration method
Authors: Korkmaz A. , Tümkaya L.
Published: November 2003

The distance between the upper and lower surfaces of a section (i.e. the section thickness) can be measured with a microcator or a shaft encoder. In the present report, an alternative simple method is described for estimating the section thickness where such equipment is not available. The basic principle of the method is based on a calibration method already described in the literature. The main difference is that it enables one to make more precise measurements. Provided that the calibration and measurements are made properly, this method can be used in estimating the section thickness, optical disector heights, and in particular in the determination of the thickness sampling fraction for the optical fractionator.
Electron‐beam‐generated carrier distributions in semiconductor multilayer structures
Authors: Mohr H. , Dunstan D. J.
Published: November 2003

The electron beam of a scanning electron microscope causes carrier generation in a semiconductor and these carriers are the probe for various types of image. In particular, the electron‐beam‐induced current mode gives images which reveal electrically active near‐surface defects in a semiconductor sample. Since semiconductor multilayer structures are now very common, one needs to know how the multilayer structure modifies the shape of the generation volume. The Monte Carlo technique for modelling beam electron trajectories inside the sample is used and gives a detailed insight into the shape of such a generated carrier generation distribution. Additionally, a simpler analytical method is developed for constructing a one‐dimensional depth distribution for multilayer structures, starting from known depth dose distributions for bulk materials. The analytical method is validated by comparison with Monte Carlo results.
Videodensitometric analysis of electron spectroscopic micrographs — a tool for detection of biologically relevant elements with high resolution
Authors: DOOR R. , BREITIG D. , MARTIN R.
Published: November 2003

Electron energy‐loss spectroscopic imaging (ESI) yields high‐resolution, element‐sensitive images. However, ESI suffers from difficulties in distinguishing element‐specific and background contributions. New methods have therefore been introduced which use grey‐level measurements in micrographic images for a more accurate detection of element distributions. A videodensitometric method allowed the detection of low phosphorus levels in axoplasmic neurofilaments of squid giant axons. Here we further verify these results by investigating the relationship of videodensitometry and electron energy‐loss spectroscopy (EELS), particularly considering the peculiarities of these methods in terms of automatic background correction and representation of the results. Six biological specimens and two nonbiological specimens were examined both by EELS and by videodensitometry. In all cases comparable results were obtained. The overlapping PL2,3 and SL2,3 ionization edges could clearly be recognized individually by both methods, and controls showed that mass density variations within the specimens did not impair elemental analysis. Additional evidence supporting the detection of phosphorylation sites in squid neurofilaments was obtained in both EELS and videodensitometric measurements of neurofilament‐enriched pellets and of aggregated axoplasmic particles. Thus, videodensitometry appears to be a useful tool for an improved exploration of the full imaging capabilities of energy filtering electron microscopy.
The effect of detector size on the extinction coefficient in confocal polarization microscopes
Authors: Higdon P. , Juškaitis R. , Wilson T.
Published: November 2003

We consider the effect of detector size on the polarization extinction coefficient in three geometries of confocal microscopes. We find that a single mode optical fibre‐based reciprocal system employing circularly polarized light offers great ease of alignment together with an extremely high extinction coefficient.
Evaluation of 26Mg stable isotope as an in vivo tracer of magnesium transport for SIMS ion microscopy imaging studies
Authors: Chandra S. , Morrison G. H.
Published: November 2003

Isotopic detection with high sensitivity, one of the most important features of ion microscopy, allows the in vivo application of stable isotopes as tracers for unravelling smaller tissue structures implicated with transport capabilities. The evaluation of the mass interferences associated with a particular mass of secondary ion signals is a necessity for tracer studies with stable isotopes. We have tested the feasibility of 26Mg stable isotope as a tracer of magnesium transport in the killifish. The fish were given a single intraperitoneal injection of 3 μmol 26MgCl2.6H2O (99.5% 26Mg enrichment), and the renal distribution of 26Mg was examined in frozen freeze‐dried cryosections with ion microscopy. High‐mass resolution analyses were performed to evaluate the purity of positive secondary ion signals of the nominal masses 24, 25 and 26 in order to assess the purity of 24Mg, 25Mg and 26Mg signals, respectively, in kidneys of control and 26Mg‐injected fish. In kidneys of control fish, the purities of 24Mg, 25Mg and 26Mg signals were ≈ 97%, 82% and 90%, respectively. In fish that were injected with 26Mg stable isotope, an enhancement of 26Mg+ secondary ion signals was observed with signal purity reaching 95%. These observations indicate that 26Mg can be used successfully as a tracer of magnesium transport in animal models. To uncover the distribution of tracer 26Mg from the naturally abundant background of this isotope, a pixel‐by‐pixel digital subtraction is applied to the raw ion microscopy mass 26 image.