bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of some instrument operating conditions on the x‐ray microanalysis of particles in the environmental scanning electron microscope
Authors: Carlton Robert A. 
Published: June 2010

AbstractThe objective of this investigation was to evaluate the practical effects of electron beam broadening in the environmental scanning electron microscope (ESEM) on particle x‐ray microanalysis and to determine some of the optimum operating conditions for this type of analysis. Four sets of experiments were conducted using a Faraday cage and particles of copper, glass, cassiterite, andrutile. The accelerating voltage and chamber pressure varied from 20 to 10 kV and from 665–66 Pa (5.0 to 0.5 torr), respectively. The standard gaseous secondary electron detectors (GSED) and the long environmental secondary dectectors (ESD) for the ESEM were evaluated at different working distances. The effect of these parameters on the presence of artifact peaks was evaluated. The particles were mounted on carbon tape on an aluminum specimen mount and were analyzed individually and as a mixture. Substrate peaks were present in almost all of the spectra. The presence of neighboring particle peaks and the number of counts in these depended upon the operating conditions. In general, few of these peaks were observed with the long ESD detector at 19 mm working distance and at low chamber pressures. More peaks and counts were observed with a deviation from these conditions. The most neighboring peaks and counts were obtained with the GSED detector at 21.5 mm working distance, 10 kV accelerating voltage, and 665 Pa (5.0 torr) chamber pressure. The results of these experiments support the idea that the optimum instrumental operating conditions for EDS analysis in the ESEM occur by minimizing the gas path length and the chamber water vapor pressure, and by maximizing the accelerating voltage. The results suggest that the analyst can expect x‐ray counts from the mounting materials. These tests strongly support the recommendation of the manufacturer to use the long ESD detector and a 19 mm working distance for EDS analysis. The results of these experiments indicate that neighboring particles millimeters from the target may contribute x‐ray counts to the spectrum.
Environmental scanning electron microscopy studies of diffusion mechanism of boron particle combustion
Authors: Yeh C. L. , Kuo K. K. , Klimkiewicz M. , Brown P. W. 
Published: June 2010

AbstractThis investigation was performed to resolve long‐term contradicting theories regarding the mechanisms which govern the species diffusion across the liquid B2O3 layer covering a single boron particle during the combustion of boron. An environmental scanning electron microscope (ElectroScan E‐3) was used to observe the liquefaction characteristics of the boron oxide layer and to examine boron dissolution and species diffusion processes in real time. Using a hot stage, crystalline boron particles were heated from 25 to 950°C in O2, H2O, or Ar environments. Pure B2O3 particles were also heated in an O2 environment and examined. In situ observations showed that the diffusion of dissolved boron into molten B2O3(1) is much more dominant at elevated temperatures than the diffusion of gaseous O2 through the B2O3(1) layer. Dissolution of solid boron into the boron oxide layer caused the liquefaction of boron particles at relatively low temperatures (940°C). The chemical composition of liquid boron oxide, coated on the surface of boron particles, was identified as a polymeric vitreous (BO)n complex through the reaction between dissolved boron and molten B2O3(1).
In situ laser heating in an environmental scanning electron microscope
Authors: Foitzik Andreas H. , Füting Manfred W. , Hillrichs Georg , Herbst Ludolf‐Johannes 
Published: June 2010

AbstractThe environmental scanning electron microscope (ESEM) offers improved capabilities for coupling a scanning electron microscope (SEM) with an in situ laser device compared with conventional SEMs. Such coupling generally enables, for example, the observation of laser glazing effects or high‐temperature behaviour as well as thermal shock behaviour of materials and devices. In an ESEM, decomposition caused by high‐temperature gas reactions can additionally be studied while monitoring the gaseous environment online with a mass spectrometer attached to the specimen chamber. In this work, we demonstrate the capabilities of an in situ laser system suitable for heating specimen in an in situ deformation stage, thus enabling the further study of the mechanical properties of materials far beyond temperatures accomplished by thermal heating stages.
Better visualization inside the environmental scanning electron microscope through the infrared chamberscope coupled with a mirror
Authors: Wight Scott A. 
Published: June 2010

AbstractClearances are tight inside the specimen chamber of the environmental scanning electron microscope (ESEM), and it is difficult to see the relative positions of detectors and specimens through the viewport. For example, the relative placement of the energy‐dispersive spectrometer (EDS) and the specimen is critical for attaining reasonable x‐ray efficiency while protecting the detector window from damage. An infrared chamberscope and mirror attachment were added to improve the visibility inside the chamber.
High‐speed operation of scanning electron microscope lenses
Authors: Thong J. T. L. , Li F. 
Published: June 2010

AbstractThe speed at which the focal properties of an iron‐shrouded magnetic electron lens can be changed is fundamentally limited by Eddy currents in the magnetic material. The effects of such Eddy currents on the lens properties can be partially compensated by modifying the lens excitation to speed up the lens response. This work considers the application of excitation pre‐emphasis techniques to scanning electron microscope lenses for small and large dynamic changes in excitation. Where transient material saturation effects come into play, attempts to further improve the lens response beyond that at the onset of saturation are futile. Under such circumstances, the use of a closed‐loop feedback arrangement is proposed that can provide a degree of response improvement.
Contact angle of water on paper components: Sessile drops versus environmental scanning electron microscope measurements
Authors: Liukkonen Annukka 
Published: June 2010

AbstractThe wetting properties of paper components and sizing agents were investigated by measuring contact angles of water drops applied by the drop test method on the sample surfaces, and by observing microscopic drops in the environmental scanning electron microscope (ESEM). The results are comparable, although measurements from the ESEM observations are approximate. The ESEM observations give insight into the wetting at the microscopic level, the formation of drops, and the spreading and absorption of water drops. Absorbent samples engulf all condensing water, resulting in a water‐ saturated swollen structure with no visible drop formation. On the nonabsorbent samples, water drops form and spread on the sample surfaces.
Objective comparison of scanning ion and scanning electron microscope images
Authors: Ishitani Tohru , Tsuboi Hideki 
Published: June 2010

AbstractCommon and different aspects of scanning electron microscope (SEM) and scanning ion microscope (SIM) images are discussed from a viewpoint of interaction between ion or electron beams and specimens. The SIM images [mostly using 30 keV Ga focused ion beam (FIB)] are sensitive to the sample surface as well as to low‐voltage SEM images. Reasons for the SIM images as follows: (1) no backscattered‐electron excitation; (2) low yields of backscattered ions; and (3) short ion ranges of 20–40nm, being of the same order of escape depth of secondary electrons (SE) [=(3–5) times the SE mean free path]. Beam charging, channeling, contamination, and surface sputtering are also commented upon.
Theoretical explanation of the relationship between backscattered electron and x‐ray linear attenuation coefficients in calcified tissues
Authors: Wong Ferranti S. L. , Elliott James C. 
Published: June 2010

AbstractX‐ray absorption and backscattered electron (BSE) microscopies are two commonly used techniques for estimating mineral contents in calcified tissues. The resolution in BSE images is usually higher than in x‐ray images, but due to the previous lack of good standards to quantify the grey levels in BSE images of bones and teeth, x‐ray microtomog‐raphy (XMT) images of the same specimens have been used for calibration. However, the physics of these two techniques is different: for a specimen with a given composition, the x‐ray linear attenuation coefficient is proportional to density, but there is no such relation with the BSE coefficient. To understand the reason that this calibration appears to be valid, the behaviour of simulated bone samples was investigated. In this, the bone samples were modelled as having three phases: hydroxyapatite (Ca10(PO4)6(OH)2), protein, and void (either empty or completely filled with polymethylmethacrylate (PMMA), a resin which is usually used for embedding bones and teeth in microscopic studies). The x‐ray linear attenuation coefficients (calculated using published data) and the BSE coefficients (calculated using Monte Carlo simulation) were compared for samples of various phase proportions. It was found that the BSE coefficient correlated only with the x‐ray attenuation coefficient for samples with PMMA infiltration. This was attributed to the properties of PMMA (density and mean atomic number) being very similar to those of the protein; therefore, the sample behaves like a two‐phase system which allows the establishment of a monotonic relation between density and BSE coefficient. With the newly developed standards (brominated and iodinated dimethacrylate esters) for BSE microscopy of bone, grey levels can be converted to absolute BSE coefficients by linear interpolation, from which equivalent densities can be determined.
Apoptotic pathways depend on the target enzymatic activity and not on the triggering agent
Authors: Luchetti F. , Mariani A. R. , Columbaro M. , di Baldassarre A. , Cinti C. , Falcieri E. 
Published: June 2010

AbstractMolt‐4 human leukemia cells were triggered to apoptosis by various agents with different mechanisms of action. Staurosporine, a protein kinase C (PKC) inhibitor; camptothecin, a topoisomerase I blocking drug; and tiazo‐furin, an inhibitor of inosine 5′‐phosphate dehydrogenase (IMPDH), were used. Ultrastructural analysis showed morphologic changes characteristic of apoptosis that were very similar for all three agents. Nevertheless, DNA oligonucleosomic fragmentation was not detectable by agarose gel electrophoresis. However, a genomic DNA cleavage appeared after pulse‐field gel electrophoresis (PFGE) in cells treated with these agents for 24 h. Furthermore, in situ nick translation (NT) showed a finely spotted nuclear labelling in staurosporine‐treated cells and a compact fluorescence after camptothecin incubation. In tiazofurin‐treated cells an intermediate pattern was found. Therefore, apoptotic agents with different mechanisms of action induced the formation of large genomic DNA fragments and very similar ultrastructural changes. Therefore, both phenomena and the closely related apoptosis progression depend on target cell machinery and not on the triggering agent.
Application of the technique of environmental scanning electron microscopy to the paper industry
Authors: Manero J. M. , Masson D. V. , Marsal M. , Planell J. A. 
Published: June 2010

AbstractThe environmental scanning electron microscope was used in conjunction with a heating stage to study in situ the polymerization process in the manufacturing of filter papers for the automotive industry. The images obtained from the video recording were converted into TIFF format with a computer program and were then analyzed using an image analyzer to assess the percentage shrinkage during the cure process. These experiments yield valuable information that is impossible to obtain with other electron microscopy techniques, for example, determining whether the polymer envelops the fibers or not, or whether there is a greater or lesser degree of anchoring between fibers.
Numerical chromosomal abnormalities detected by atomic force microscopy
Authors: Ergün Mehmet Ali , Tan Erdal , Şahin Feride Iffet , Menevşe Adnan 
Published: June 2010

AbstractThe numerical abnormalities of human metaphase chromosomes, fixed according to standard procedures for optical microscopy but not treated for banding, were detected by atomic force microscopy (AFM). High‐resolution AFM imaging of chromosomes in trisomy 13, 21, and Klinefelter syndrome can be compared directly with the traditional optical image. The unbanded metaphase chromosomes, including the extra ones in trisomic patients showed a structural pattern very similar to G‐banding. Comparison of AFM images with light microscopic data allows the identification of specific chromosomes, and images of chromosomes showing numerical and structural abnormalities can then be analysed.
Thickness determination of ultra‐thin films using backscattered electron spectra of a new toroidal electrostatic spectrometer
Authors: Schlichting F. , Berger D. , Niedrig H. 
Published: June 2010

AbstractBackscattered electron spectroscopy offers detailed information for multilayer and subsurface‐layer materials with distinct Z contrast: It can be used for the validation of Monte Carlo calculations, to obtain depth selective electron microtomographic images, and to determine the thickness of ultra thin films on bulk substrates. In this paper we describe a new energy‐dispersive method for thickness determination of thin films on bulk aluminum using backscattered electron (BSE) spectra obtained by a polar, toroidal, electrostatic spectrometer. After a brief recapitulation of the spectrometer's geometry, the techniques for its energy calibration and the preparation of thin double‐layer films are introduced. Backscattered electron measurements and thickness calibrations for Au and Cu films with thicknesses of 0–200 nm on bulk aluminum will be presented for various primary electron energies.
Evaluation of scanning electron microscopy images of a model dressing using image feature extraction techniques and principal component analysis
Authors: Egelandsdal Bjørg , Christiansen Kirsti F. , Høst Vibeke , Lundby Frank , Wold Jens Petter , Kvaal Knut 
Published: June 2010

AbstractTwelve dressing systems made by varying protein type, oil level, CaCl2, NaCl, and sucrose, were examined using scanning electron microscopy. Images from the 12 systems were quantitatively analysed using methods of feature extraction. These methods were based on vectorisations of the images followed by principal component analysis on the extracted vectors. These techniques were used to examine the reproducibility of the acquired images as well as to relate the images to rheologic and sensory texture parameters. Two feature extraction methods were used: the angle measure technique (AMT) and the absolute difference method (ABDF). The ABDF method used fewer principal components to extract information from images relevant to the complex modulus/sensory viscosity of the system, but the information seemed equally well preserved by the two‐feature extraction methods. The AMT was more efficient in classifying the images with respect to protein type. A fair correlation between images and complex modulus was obtained (R=0.73). It is suggested that a better correlation might be obtained by adding more systems, increasing the number of areas imaged for each system as well as avoiding systems of low viscosity.
Surface roughness of preparations for backscattered electron‐scanning electron microscopy: The image differences and their monte carlo simulation
Authors: Howell P. G. T. , Boyde A. 
Published: June 2010

AbstractPatterns and levels of mineralisation in the biological hard tissues have been studied using the backscattered electron (BSE) mode in the scanning electron microscope (SEM). To prevent gross topographic detail overwhelming changes in signal from composition, samples are embedded in polymethylmethacrylate (PMM A) and a flat block surface produced by polishing or micromilling. This study was undertaken to establish the degree of residual topography achieved in these finishing processes. A sample of human rib was embedded in PMMA and prepared, as for examination in the SEM, by polishing on graded abrasives and pre‐ and, finally, ultra‐milling. After each preparation step, the block face was imaged using a confocal reflection microscope surface mapping facility. The recorded topographies were used in a Monte Carlo simulation to model the surface interface and thus, for each of the sample preparation techniques, to calculate predicted variations in BSE signal. The latter were compared with experimental data derived under standard operating conditions in the SEM. Micromilling produced block faces with typical peak‐trough relief of 80 nm, while hand polishing left occasional scratches 1.5 μm deep with a general undulation of 150–250 nm. Monte Carlo simulations of a rough surface of bone using these data predicted that additional contrast levels of 5% could be expected from micromilled surfaces and > 10% for hand polished samples of bone. Thus, micromilling is the best preparation method for bone, since this tissue develops a collagen orientation‐related relief on polishing, which may be largely responsible for the (incorrect) supposition that lamellation in bone is related to changes in net degree of mineralisation.
The mechanism of G‐banding detected by atomic force microscopy
Authors: Şahin Feride Iffet , Ergün Mehmet Ali , Tan Erdal , Menevşe Adnan 
Published: June 2010

AbstractThe morphologic changes occurring in human chromosomes during G‐banding by trypsin treatment on the same metaphase were followed with the aid of an atomic force microscope (AFM). It was found that trypsin treatment alone caused a pattern of collapse in the chromosomes that was clearly dependent on the duration of trypsinization. The progressive pattern of collapse first indicated the loss of internal differentiation between chromatids, then bands, and finally all internal structures, except for edges running around the chromosomes' perimeter. When stained with Giemsa, the collapsed chromosomes partly regained their original form, and transverse ridges appeared that correspond to G‐positive band regions. However, the treatment of fixed chromosomes with trypsin for 42 s diminished the chromosomal edges, and the z‐dimensions could not be measured even with the subsequent application of Giemsa.
Determination of secondary electron spectra from insulators
Authors: Yong Y. C. , Thong J. T. L. 
Published: June 2010

AbstractA new technique for the determination of secondary electron (SE) spectra of insulators in a scanning electron microscope environment is presented. It is based on a capacitatively coupled charge measurement by subjecting the insulating film to a controlled pulsed electron beam. With the use of a planar grid analyzer configuration, an algorithm is used to estimate the SE spectrum based on normalized values of the S‐curve obtained. Secondary electron spectra from several insulating materials employed in integrated circuit manufacturing, including silicon nitride (Si3N4), AZ 1350J photoresist, and pyralin polyimide, have been measured.
Thermal effects of the electron beam and implications of surface damage in the analysis of bone tissue
Authors: Holmes Jennifer L. , Bachus Kent N. , Bloebaum Roy D. 
Published: June 2010

AbstractElectron beam interactions with specimens in the scanning electron microscope (SEM) can lead to increased surface temperatures and damage. These changes may have significant consequences in the analysis of bone tissue. An investigation was performed to measure the surface temperature changes associated with the electron beam on a thermocouple with systematic variations in operating conditions. Probe currents, magnifications, and accelerating voltages were incrementally adjusted to measure the temperature changes and to make assessments for determining optimal operating conditions for the SEM in future analyses of bone tissue. Results from this study suggest that thermal effects were minimal at lower accelerating voltages (< 20 kV), lower probe currents (< 10 nA), and lower magnifications, but surface damage may still occur during the analysis of bone tissue.
Three‐dimensional reconstruction and motion analysis of living, crawling cells
Authors: Soll David R. , Voss Edward , Johnson Olof , Wessels Deborah 
Published: June 2010

AbstractCell behavior is three‐dimensional (3‐D), even when it takes place on a flat surface. Migrating cells form pseudopods on and off the substratum, and the cell body undergoes height changes associated with a 1 min behavior cycle. Inside the cell, the nucleus has a 3‐D migratory cycle, and vesicles move up and down in the z‐axis as a cell locomotes. For these reasons, the two‐dimensional (2‐D) analysis of cellular and subcellular behavior is, in many cases, inadequate. We have, therefore, developed 3‐D motion analysis systems that reconstruct the cell surface, nucleus, pseudopods, and vesicles of living, crawling cells in 3‐D at time intervals as short as 1 s, and compute more than 100 parameters of motility and dynamics morphology at 1‐s intervals. We are now in the process of developing a multimode reconstruction system that will allow us to reconstruct and analyze fluorescently tagged molecular complexes within the differential interference contrast‐imaged subcellular architecture of a crawling cell. These evolving technologies should find wide application for a host of biomedical problems.
Field‐emission scanning electron microscopy of the internal cellular organization of fungi
Authors: Müller Wally H. , van Aelst Adriaan C. , Humbel Bruno M. , van der Krift Theo P. , Boekhout Teun 
Published: June 2010

AbstractInternal viewing of the cellular organization of hyphae by scanning electron microscopy is an alternative to observing sectioned fungal material with a transmission electron microscope. To study cytoplasmic organelles in the hyphal cells of fungi by SEM, colonies were chemically fixed with glutaraldehyde and osmium tetroxide and then immersed in dimethyl sulfoxide. Following this procedure, the colonies were frozen and fractured on a liquid nitrogen‐precooled metal block. Next, the fractured samples were macerated in diluted osmium tetroxide to remove the cytoplasmic matrix and subsequently dehydrated by freeze substitution in methanol. After critical point drying, mounting, and sputter coating, fractured cells of several basidiomycetes were imaged with field‐emission SEM. This procedure produced clear images of elongated and spherical mitochondria, the nucleus, intravacuolar structures, tubular‐ and plate‐like endoplasmic reticulum, and different types of septal pore caps. This method is a powerful approach for studying the intracellular ultrastructure of fungi by SEM.