bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping the composition of materials at the atomic level
Authors: Ourmazd A. , Baumann F.H. , Kim Y. , Kisielowski C. , Schwander P.
Published: June 2020

This paper briefly outlines how transmission electron microscopic lattice imaging techniques can be used to map the composition of crystalline materials at the atomic level.

Under appropriate conditions, a conventional lattice image is a map of the sample structure, because the dominant reflections used to form lattice images are relatively insensitive to compositional changes in the sample. Such reflections may be termed “structural”. In many cystalline materials, compositional changes occur by atomic substitution on a particular subset of lattice sites. In these systems, compositional changes are accompanied by the appearance of reflections, which we name “chemical”. Such reflections, for example the (200) in the zinc-blende structure, owe their existence to chemical differences between the various atomic species present on the different lattice sites. For fundamental reasons these reflections are often weak; they come about because of incomplete cancellation of out of phase contributions from different sublattices. “Chemical lattice imaging” exploits dynamical scattering to maximize the intensity of such reflections, and uses the objective lens as a bandpass filter to enhance their contribution to the image.
A non-imaging concentrator for fiber optic mediated remote micro-Raman spectroscopy
Authors: McKinley B. J. , Sheem Sang , Lutz John , Milanovich Fred P.
Published: June 2020

The recent availability of moderate power near-infrared diode lasers (780nm) and near-infrared sensitive ccd detectors have caused a noticeable resurgence in the application of Raman spectroscopy in analytical chemistry. We have long maintained an interest in Raman spectroscopy and have established a micro-Raman facility within the Chemistry Department of our organization. Recently, we have taken advantage of the aforementioned progress in spectroscopic equipment and have upgraded our micro-Raman facility to include a ccd detector and an imaging spectrograph.

Since our micro-Raman spectrometer is designed around an ellipsoidal collection mirror, with Raman signal being directed through the illumination sample stage it has application to microscopic or small transparent samples. The improved performance of the device and the availability of highly transmissive optical fibers led one of us (B.J.M.) to propose an apparatus that could replace the existing illuminator with a miniature device that maintains a high collection efficiency and can be used remotely or in-situ by utilizing optical fibers.
Fluorescence imaging by confocal microspectrometry
Authors: Da Silva E. , Lenain B. , Manfait M.
Published: June 2020

Confocal microfluorometry possesses many advantages. In particular, it provides the possibility to control the size of the analyzed surface and the depth of focus.

The laser focussed on a line under microscope has been achieved either with cylindrical optics or by spot deflection (to conserve the Gaussian distribution of the laser beam).

Associated with a 2D detector, this focussed line gives the spectral distribution for all the points of the line. A motorized stage in the direction perpendicular to the line gives all the data to rebuild a spectral image.

We present a new scanning method rigorously confocal and giving, in addition, the possibility to change continuously the spread factor (defined by the number of pixels of the detector divided by the dimension of the line onto the sample under microscope), from few pixels by micrometer up to 20 pixels by micrometer.

Figure 1 shows the principle of the system; a first optical scanner scans a line onto the sample under microscope.
Biological applications of near- IR fourier-transform Raman microspectroscopy
Authors: Ozaki Yukihiro
Published: June 2020

Recently-developed near-infrared Fourier transform (FT)-Raman spectroscopy has received keen interest of researchers in bio-Raman field because near-infrared excitation can avoid mostly fluorescence and photodecomposition, which have been two major drawbacks of Raman spectroscopy in its biological and medical applications. Introduction of FT-Raman microspectroscopy makes near-infrared FT-Raman spectroscopy more useful for studying biomedical materials. The purpose of the present paper is to demonstrate the potential of near-infrared FT-Raman microspectroscopy in nondestructive structural analysis of biological systems. Photosynthetic bacteria is taken up here as an example.

The FT-Raman spectra of the photosynthetic bacteria were measured with a JEOL JRS-FT6500N FT-Raman spectrometer equipped with an optical microscopy. Excitation wavelength at 1064-nm was provided by a CW Nd:YAG laser (CVI YAGMAX c-92), and the laser power at the sample position was typically 150 mW. All the data were collected at a spectral resolution of 8 cm-1 and spatial resolution of 8 μm.
Microstructure of superconductor bulk materials and thin films
Authors: Huong Pham V.
Published: June 2020

The microstructure of single crystals of Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O prepared by different methods were studied by various physical techniques, in particular by Raman microspectroscopy.

Correlations have been established between Raman spectra and structure, allowing the determination of crystalline geometry of the material versus the composition and the preparation parameters.

For YBa2Cu3Ox, a relationship: x = 0.025 VH - 5.57 is proposed and permits to evaluate the oxygen content by measuring simply in ZZ scattering geometry the Cu-O stretching mode V'H along the c axis of the crystal. This frequency varies from 465 cm-1 in YBa2Cu3O6 to 503 cm-l in YBa2Cu3O7 (Fig.l).

This technique also offers the possibility to follow the structural conversion Y124 into Y123 and TI2212 into TI1212 (Fig.2) by appropriate thermal treatment. The preferentiel departure of the “CuO” or “TIO” chain/layer (Fig.3) is explained by weaker interaction forces between these layers and the adjacent ones, compared to those between the remaining layers. This helps to predict the localization of an eventual intercation in Y123 and TI1212.
Elemental changes in hepatocyte couplet cell cultures following treatment with vasopressin
Authors: Tsukada N. , Ackerley CA. , Phillips M.J.
Published: June 2020

Hepatocyte couplet cell cultures have been used as a cell model to study the contractile nature of the bile canaliculus. It is generally accepted that a rise in cytoplasmic Ca activates the actomyosin ATPase resulting in the contraction of the pericanalicular actomyosin complex and the closure of the bile canaliculus. Vasopressin, a Ca mobilizing hormone, has been shown to increase the cytoplasmic Ca and induce bile canalicular contraction.

In the present study rat hepatocyte couplet cultures were prepared as described by Oshio and Phillips. After 4 hours the volume of the culture media was decreased and the cells were liberated from the culture surface with a rubber policeman. Cells were then treated with vasopressin at a concentration of 10-9 M for time periods of 0, 30, 60,90, 120, 180, 240 and 300 seconds and drops of cell suspension were frozen by either slam freezing them on a liquid nitrogen cooled, highly polished copper anvil or plunge freezing them into liquid nitrogen cooled ethane.
Quantitative EELS mapping of biological thin sections
Authors: Wang Y.Y. , Shao Z. , Ho R. , Somlyo A.V. , Somlyo A.P.
Published: June 2020

X-ray microanalysis and electron energy loss spectroscopy are reliable methods for determining at high spatial resolution the local composition of biological materials. EELS imaging, although potentially more sensitive than X-ray analysis, is complicated by the large background of EELS spectra. The conventional power law fitting of the EELS background can only be used for analysis of high concentrations and/or very thin sections (t< 0.3 λ) and it is not reliable for mapping low elemental concentrations. For the detection of low elemental concentrations at high spatial resolution, the background subtraction of the EELS spectrum and correction of long term microscope drift are critical, and limit the use of conventional energy filtered transmission electron microscopy. Therefore, we used energy filtered STEM with multiple least squares fitting, including the plural plasmon contribution to the background, to obtain quantitative phosphorus (P) and calcium (Ca) concentration maps of cryosections.

The failure of the power law is due to the plural scattering contributions to the Background.
A technique to obtain quantitative water measurements from high-resolution STEM images of biological specimens
Authors: Warner Ronald R. , Lilly North A. , Hay worth Mark S.
Published: June 2020

Water content is an important parameter in many biological and medical investigations, such as volume regulation in cell biology, osmotic adaptation in physiology, and cell injury in pathology. Of existing methodologies for quantitative water measurements, analytical electron microscopy offers unique opportunities for absolute quantitation of water in subcellular volumes within any region of a tissue. Water quantitation by AEM analysis is typically done by measuring the x-ray continuum intensity in a freeze-dried specimen and comparing the continuum with that from a standard of known water content using the Hall or Rick approach. However, this AEM data is obtained at great cost in time, usually by stationary probe measurements. Often large numbers of analyses must be averaged to obtain meaningful results. Mass loss (etching) or mass gain (contamination) during analysis seriously complicates the water measurement. We have developed an alternative technique that eliminates or minimizes these problems. Our technique is similar to the Rick procedure, and similar assumptions apply.
X-ray microanalysis of intracellular ions in epithelial tissues
Authors: Rick Roger
Published: June 2020

Electron probe x-ray microanalysis provides a powerful tool in studying transepithelial ion transport mechanisms as it allows the quantitative detection of diffusible ions on a cellular and subcellular scale. The high spatial resolution afforded by this method is of particular advantage in epithelial tissues that are composed of different cell types and cases in which the transcellular transport pathway might involve different intracellular compartments. In the following, the methods applied in several studies are described, with emphasis on some recent modifications.

The tissues are frozen by rapid immersion in liquified ethane kept at -180°C. Support systems for different epithelial preparations have been developed to facilitate freezing and maintain the functional state of the epithelium immediately up to the moment of freezing. A fluid-clamp technique is used to mount the tissue for sectioning (Figure 1). Sections are cut dry at -140°C and a nominal thickness of 200 nm using 40° glass knifes. The sections are picked up from the back of the knife by a fire-polished wire probe (1 μm tip diameter) and placed on a parlodion film which is suspended over a 2 mm opening in a special beryllium carrier disc.
An analytical and ultrastructural investigation of bone mineral in brittle bone disease (osteogenesis imperfecta).
Authors: Cassella J.P. , Catterall A.C. , Stamp T.C.B. , Yousuf Ali S.
Published: June 2020

No single analytical technique will provide all the information necessary for the interpretation of a complex biological system. The mineralisation of bone is no exception, especially in a pathological situation. Brittle Bone disease, a genetically and biochemically heterogeneous group of disorders is characterised by the ease and frequency of bone fracture. Although Type I procollagen mutations have been detected, few reports exist of the mineral and its relationship with the altered collagen.

X-Ray Microanalysis (XRMA), X-Ray Powder Diffraction (XRPD), Fourier Transform Infra Red spectroscopy (FTIR) and31p Nuclear Magnetic Resonance spectroscopy (31P NMR) were used to study the composition, structure and resonance of the calcium-phosphate (Ca-P) in bone. Specimens of bone were fixed in 2.5% gluteraldehyde solution (18 hours) at 40C. The specimens were cut into small pieces (1-3mm3) during the first hour of fixation, followed by secondary fixation in 1% osmium tetroxide. The tissue was dehydrated through a graded series of ethanols before vacuum infiltration and embedding in Spurr's resin for 18 hours at 600C.
Importance of the relative x-ray line intensities
Authors: Lábár János L. , Fiori Charles E. , Myklebust Robert L.
Published: June 2020

Relative intensities of the non-analytical lines of an element (as compared to the analytical X-ray line of the same element) directly affect the accuracy of quantitative X-ray microanalysis. Correct spectral deconvolution can only be based on the knowledge of these relative intensities. Not even wavelength dispersive spectrometry (WDS) is free from spectral overlaps, making deconvolution of the X-ray lines necessary. A typical example for such a serious overlap can be the L line series of different rare-earth elements simultaneously present in the same sample. Energy dispersive spectrometry (EDS) is even more affected. Many EDS systems are equipped on scanning electron microscopes (SEM). Quick standardless analysis is frequently in use in these systems. Starting approximation of the elemental concentrations are based on computed "standard intensities" in contrast to measured ones in full quantitative analysis. Computation of the generated standard intensities directly contain the relative intensities of other lines too.
Testing ZAF and related procedures
Authors: Heinrich Kurt F. J.
Published: June 2020

Conventional ZAF procedures, Pouchou and Pichoir's PAP and XPP procedures (transcribed into a ZAF format), Scott and Love's procedure, and the f(ρz) procedures by Brown and by Packwood (all described in ref.) were tested by a modular program in Turbopascal which permits selecting separately the procedures for electron deceleration, backscattering (except the ϕ(ρz) procedures),absorption, fluorescence by characteristic and by continuous radiation. Parameters such as the absorption coefficient, the J factor, fluorescent yield and inner shell cross section can also be selected from the menu.

The data used for the evaluation are from binary specimens. They were collected from publications by various authors, with addition of some unpublished data generated at NBS by R. Marinenko and H. Konuma. The following data types were excluded:

1.

most data obtained with x-ray emergence angles below 30°.

2.

single values, not corroborated by measurements of other concentrations or under other experimental conditions.

3.

sets of measurements showing lack of internal consistency.
In-depth profiling with the electron-probe microanalyzer
Authors: Bastin G. F. , Dijkstra J. M. , Heijligers H. J. M.
Published: June 2020

In a recent publication we have given a brief outline of the procedure we followed in extending our “PROZA” φ(ρ·z) bulk matrix correction program into a thin film analysis program. With such a program it is possible to determine film thicknesses and compositions of a number of films simultaneously using measured intensity ratios of all elements involved as input. As long as each particular element in the layered system is confined only to one specific layer or the substrate only one measurement for each element at one suitable accelerating voltage will be sufficient to find thicknesses and compositions in a double iterative procedure. If one or more elements occur in more than one film or also in the substrate then more measurements over a suitable range in accelerating voltages are necessary.

The ultimate challenge in multi-layer analysis is, beyond any doubt, the determination of the concentration-distribution as a function of depth for all the elements in a particular matrix.
Monte Carlo Simulation of Background in electron spectroscopies
Authors: Shimizu Ryuichi , Yoshikawa Hideki
Published: June 2020

Recent progress in getting precise knowledge on inelastic scattering, particularly, on dielectric functions for various types of material has been enabling the electron spectroscopic spectra obtained by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS) to be reproduced theoretically with considerable success. For this Monte Carlo simulation is probably most powerful tool, leading to more comprehensive understanding of not only the signal generation but also the background formation.

In this paper we present a Monte Carlo simulation approach based on the uses of Mott-scattering cross section and appropriate dielectric function for describing elastic scattering and inelastic scatterings, respectively. With respect to the dielectric function one can use, to good approximation in general, the optical dielectric constants from the data base provided by synchrotron radiation facilities.

As typical examples of the Monte Carlo simulation the applications to the AES, XPS, and REELS are shown in Figs. 1, 2, and 3, respectively. The N(E)-spectrum in Fig.l demonstrates how the Monte Carlo simulation describes the energy loss spectrum due to plasmon excitation near at primary energy, general shape of energy distributions of backscattered electrons and secondary electrons.
An application of photoemission microscopy to failure analysis of complex silicon integrated circuits
Authors: Golijanin Danilo
Published: June 2020

Emission of visible light from forward and reverse biased silicon p-n junctions due to the radiative electron-hole recombination has been known since the mid-50s. The weak light emission was also seen from a silicon-dioxide dielectric in an integrated gate oxide capacitor formed between a polysilicon gate and an (n or p) well in an integrated circuit. The difference in carrier energies for each of these recombination mechanisms gives rise to a specific photon wavelength (energy) distribution in the visible range. All photoemitting events are characterized by a very low level light intensity due to the low quantum efficiency of about 10−5 - 10−4 photons per one electron-hole recombination.

The first practical photoemission microscope was constructed by Khurana and Chiang. They took the advantage of the advances in night vision technology and used it for imaging the faint ("invisible") light coming from various silicon structures. A typical photoemission microscope consists of an x-y-z stage with the device holder, an optical microscope, a lightsensitive camera all set within a light-tight enclosure and a computer system for image acquisition and processing.
Measurement of silver diffusion in thick-film resistors by energy-dispersive x-ray techniques
Authors: Bonavita James C
Published: June 2020

Material from some silver terminations used in metal-ceramic circuit applications can diffuse into the overprinted thick film resistor layers when the chips are repeatedly heated to a series of firing temperatures (∼850°C) during the fabrication process. Both materials have complex glass-based compositions and interdiffusion depends on the combination of materials, and conditions, involved. A discoloration is observed due to the migration of silver, in the form of the oxide, and the electrical properties of the resistor may be significantly modified. As might be expected, the deviation from ideal behavior, and therefore changes in resistor properties, are more serious for the smaller geometry resistors bridging narrow gaps between the silver conductor tracks.

Direct SEM energy dispersive x-ray (EDX) analysis in plan view (Fig.1) of selected regions of complete chips - without any additional specimen preparation - has been used to determine the extent of the migration into the bridging region of the resistor. The measured lateral range of the silver cation migration is up to ∼500μm : this is much larger than the typical ∼10μm thickness of the resistor layer.
Microanalyses of antarctica micrometeorites
Authors: Maurette M. , Perreau M.
Published: June 2020

About 260 tonnes of ultraclean blue ice were recently melted and filtered on the Antarctic ice sheet (in January 1991, at Cap-Prudhomme, near the french station of Dumont d'Urville) as to collect all grains with sizes > 25 μm. In the best size fraction (50-100μm) about 10% of the grains are unmelted antarctic micrometeorites (AMMs) with a chondritic composition. About 50% of these grains are complex aggregates of submicron-sized grains. Their characterization, which is very difficult, requires a panoply of analytical techniques allowing their analyses at all scales of magnification between 106 μm3 and 10-4 μm3. We review below analyses performed by various groups, and discuss briefly some of their preliminary implications to various fields of Science.

The "large" size of the AMMs allows their multidisciplinary investigations. With a binocular we start selecting an aliquot of ≈50 dark grains showing irregular shapes, and which usually contains about 70% AMMs. Each grain is broken into about 4 fragments and their multidisciplinary analysis proceeds as follow: (1) Polished sections. The largest of these fragments are mounted in an epoxy disc and polished.
An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement
Authors: Carpenter D. A. , Taylor M. A.
Published: June 2020

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.

The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.
Analysis of individual microscopic particles by means of synchrotron radiation induced x-ray micro fluorescence
Authors: Janssens K. , Adams F. , Rivers M.L. , Jones K.W.
Published: June 2020

Micro-SXRF (Synchrotron X-ray Fluorescence) or micro-SRIXE (Synchrotron Radiation Induced X-ray Emission) is a microanalytical technique which combines the sensitivity of more conventional microchemical methods such as Secondary Ion Microscopy (SIMS) and μ-PIXE (Proton Induced X-ray Emission) with the non-destructive and quantitative character of X-ray fluorescence analysis. The detection limits attainable at current SXRF-facilities are situated in the ppm (and in favourable cases the sub-ppm) range. The sensitivity of SRIXE can be used advantageously in individual particle analysis. This type of analysis is used, e.g., for studying sources of athmospheric pollution. Analysis of standard NIST micro-spheres at the NSLS-SRIXE facility yielded minimum detection limits in the 1 to 100 ppm range for particle sizes of around 10 to 30 μm.

An interesting approach to individual particle characterisation is by means of electron microprobe analysis (EPMA). By using the backscattered electron signals, in an automated fashion, particles can be easily located on a filter substrate and their size and shape determined.
Multitechnique problem solving using EDS/EPMA and surface analysis
Authors: Simko Steven J. , Waldo Richard A.
Published: June 2020

Thin films are used in a wide range of modern technologies. Examples include sensors, antiwear coatings, optical coatings, and integrated circuits. A variety of methods have evolved for characterizing thin films in the thickness range of 1 monolayer to several micrometers. Electron probe microanalysis (EPMA) or energy dispersive x-ray spectroscopy (EDS) are two methods for characterizing thicker films (>1 μm). In these techniques, the sampling depth depends on the penetration depth of the primary electron beam which can be controlled by changing the electron beam energy. Thin films can also be characterized using line scans on specimens prepared as polished cross-sections or after angle lapping. For extremely thin films (<3 nm), techniques with high surface sensitivity such as Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) are commonly employed. Sampling depth depends on the attenuation length of the emitted photoelectrons or Auger electrons.

Electron spectroscopy techniques are also used to characterize thicker films by adding a microsectioning method to the experiment, most commonly ion sputtering.
Inner-Shell Ionization Cross Sections
Authors: Powell C. J.
Published: June 2020

Values of cross sections for ionization of inner-shell electrons by electron impact are required for electron probe microanalysis, Auger-electron spectroscopy, and electron energy-loss spectroscopy. The present author has reviewed measurements and calculations of inner-shell ionization cross sections. This paper is an update and summary of these previous reviews.

It is convenient to start with the Bethe equation for inner-shell ionization cross sections which is frequently used (and misused) in x-ray microanalysis:

(1)

where σnℓ is the cross section for ionization of the nℓ shell with binding energy Enℓ by incident electrons of energy E. The terms bnℓ and cnℓ are the Bethe parameters discussed further below. It has been assumed in the derivation of Eq. (1) that E ≫ Enℓ ; this requirement will also be discussed. Finally, it has been assumed here that E is low enough (≲50 keV) so that a relativistic correction is unnecessary.

The extent to which a given set of measured or calculated cross-section data is consistent with Eq. (1) can be determined from a Fano plot in which σnℓE is plotted versus ℓnE; if such a plot is linear, Eq. (1) is consistent with the data and values of the Bethe parameters can be easily derived.
Electron Energy-Loss Near-Edge Structures as a Probe of Solids
Authors: Engel W. , Sauer H.
Published: June 2020

In general, core-level spectra show a very pronounced structure beyond the edge up to about 20 eV. This is called the near-edge structure, and in the case of electron energy-loss spectra its acronym is ELNES. ELNES is due to transitions of electrons from a particular core level to the lowest unoccupied states in the solid. This provides information about the local electronic structure of the solid at the site of the excited atom, and may depend very sensitively on the arrangement of the neighbouring atoms.

This effect is demonstrated in a series of Ti 2p core-level spectra shown in Figs. 1 and 3 which have been obtained from various tetravalent titanium compounds. In all these compounds the Ti4+ ions are surrounded by 6 oxygen atoms but they form perfect octahedra only in the case of SrTi O3. In the other compounds the oxygen octahedra are more or less distorted, giving rise to a splitting or broadening of peaks.
An Application of 200kV Ultrahigh Resolution Analytical Electron Microscope
Authors: Suzuki M. , Kaneyama T. , Watanabe E. , Naruse M. , Kokubo Y.
Published: June 2020

A 200 kV ultrahigh resolution analytical electron microscope (UHRAEM), JEM-2010, enables both ultrahigh resolution imaging with a theoretical point resolution of 0.194 nm and nm-area analysis. In this paper, its preliminary data for x-ray analysis (Energy Dispersive X ray Spectroscopy: EDS) and its application data will be shown.

An objective lens polepiece has been designed to minimize the spherical aberration coefficient (Cs) of the prefield and thereby increase the probe current in small probe size for nm-area EDS analysis. Measured values of Cs and chromatic aberration coefficient (Cc) are 0.5 mm and 1.0 mm, respectively. Fig. 1 shows a theoretical relation between the illumination angle and probe size of this objective lens on the assumption that the brightness of electrons is 6×106A/cm2• str in a LaB6cathode. This calculation shows that an electron probe smaller than 1 nm in diameter is available even with a probe current of 10 pA.
Post-Spectrometer Instrumentation for STEM
Authors: McMullan D. , Rodenburg J.M. , Pike W.T.
Published: June 2020

A charge-coupled device (CCD) is being used for parallel recording on the EELS spectrometer of the V-G HB501 STEM in the Cavendish. Three quadrupole lenses are provided for focussing the EELS spectrum and, unlike in some other similar systems, the spectrometer slit has been retained. This was done so that the spectrometer could still be used for serial acquisition of EELS spectra and for energy-filtered imaging, although it would be preferable, and was envisaged as a later development, to have the first quadrupole positioned before the dispersion plane of the spectrometer; the slit would have been simulated by a suitably masked scintillator for the bright field detector.

However it has proved advantageous to keep the slit so that microdiffraction patterns can be imaged through the spectrometer. The recording of high quality diffraction patterns in the HB501 STEM has not been straightforward: Grigson recording is far too slow, and although the standard microscope is provided with a phosphor screen and TV and film cameras, the speed and resolution are rather poor.
Quantitative EPXMA imaging of rapidly frozen kidney proximal tubule primary cultures
Authors: Spencer A.J. , Hawkey L.A. , LeFurgey A. , Dickman K.G. , Mandel L.J. , Ingram P.
Published: June 2020

Understanding the role of elements/ions (particularly calcium) in processes such as cellular injury in the kidney requires not only assessment of total cell element and its cytoplasmic free ion, but also identification of the sites of release, uptake and binding of those ions/elements within the cells and correlation with physiological lesions such as changes in cell metabolism. Short term anoxia (40min) does not appear to alter Ca compartmentation in kidney proximal tubule cells. However, the effects of longer periods of anoxia and subsequent recovery have not been studied due to the lack of a suitable in vitro model. Quantitative electron probe x ray (EPXMA) imaging facilitates assessment of cell ultrastructure and measurement of total element with high lateral spatial resolution. We have therefore applied EPXMA imaging to a recently described preparation of primary kidney proximal tubule cultures, which retain the in vivo metabolic features of proximal tubules for longer periods of time in vitro.
Opening images of synaptic vesicles and calcium localization by means of microwave fixation method
Authors: Mizuhira Vinci , Hasegawa Hiroshi
Published: June 2020

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.
Searching for the causes why some of the paintings by Mihaly Munkacsy are darkening
Authors: Pozsgai Imre , Erdöhalmi-Torok Klara
Published: June 2020

The paintings by the great Hungarian master Mihaly Munkacsy (1844-1900) made in an 8-9 years period of his activity are deteriorating. The most conspicuous sign of the deterioration is an intensive darkening. We have made an attempt by electron beam microanalysis to clarify the causes of the darkening. The importance of a study like this is increased by the fact that a similar darkening can be observed on the paintings by Munkacsy’s contemporaries e.g Courbet and Makart. A thick brown mass the so called bitumen used by Munkacsy for grounding and also as a paint is believed by the art historians to cause the darkening.

For this study, paint specimens were taken from the following paintings: “Studio”, “Farewell” and the “Portrait of the Master’s Wife”, all of them are the property of the Hungarian National Gallery. The paint samples were embedded in a polyester resin “Poly-Pol PS-230” and after grinding and polishing their cross section was used for x-ray mapping.
A method to overcome the problem of small sample tilts in light element electron microprobe analysis
Authors: Mackenzie Andrew
Published: June 2020

The technique of electron microprobe analysis is extremely useful in the rapidly changing field of high temperature superconductivity. Since the properties of the oxide superconductors depend strongly on the oxygen concentration, it is important to be able to measure oxygen as accurately as possible. It is particularly useful to know unambiguously the composition of small single crystals, which either grow with good smooth surfaces (for example in the Y-Ba-Cu-O system) or can be easily cleaved (for example the Bi-Sr-Cu-O system) to provide excellent surface quality without polishing. The Bi2+xSr2-x,CuO6±z (BSCO) crystals are extremely soft and layer like, which makes polishing difficult, and another advantage of cleaving is that the crystal does not have to be embedded in epoxy, and can thus be relatively easily removed from its mount for subsequent annealing treatments or other experiments. The disadvantage of mounting in this manner is the existence of small tilt angles, because the thin crystals bend a little when they are cleaved.
Valence state analysis of elements by EPMA and its application
Authors: Liqing Chen , Zuqin Liu , Wei Zhang
Published: June 2020

Valence state analyses of Fe and Mn in oxides by EPMA have been reported in literature. In this paper, the effects of valence state on intensity ratios ILα/IKα and ILα/ILβ of Cu, Ni, Co, Fe, Mn, Cr and their oxides, and on intensity ratios ILβ2/ILα1 and ILγ1/ILα1 of Mo, Nb, Zr and their oxides were studied. It was observed that intensity ratios change with valence states in accordance with some regularities, and these effects could be utilized for analyzing the valence states of catalysts.

Valence state analysis of elements by EPMA is based on the fact that changes in the states of valence electrons in the outer shells of an atom cause corresponding changes in line intensities. The M electrons of Cu, Ni, Co, Fe, Mn, Cr and the N electrons of Mo, Nb, Zr are valence electrons. Line Kα1,2 and six lines of L are produced from the transitions of K-L2,3 and L-M or L-N respectively.
Quantitative E. D. Analysis At High Count-Rates
Authors: Reed S.J.B.
Published: June 2020

Hitherto quantitative E.D. analysis has been carried out generally at pulse throughput rates up to about 5 kHz. Some commercially available E.D. systems are, however, now capable of rates exceeding 30 kHz. The present study is concerned with the feasibility of quantitative analysis at high count-rates, with the emphasis on applications to geological samples, especially silicates. Benefits of high count-rates include reduction in the time required per quantitative analysis. Also lower detection limits are obtainable with a constant time. Furthermore, flexibility with regard to count-rate is useful in combined E.D. and W.D. analysis.

The Link Analytical XP2 pulse processor used in this study has a choice of 6 ‘process times’ (equivalent to the peaking time in a conventional amplifier). The throughput (or output) rate as a function of input count-rate for process times 1-4 is shown in Figure 1. The shortest (no. 1) gives a maximum throughput rate of 32 kHz, the dead time per pulse being 12 μS.
Sub-Micron Spatial Resolution Edx Microchemical Analysis Of Bulk Specimens In The Sem At Low Beam Voltages
Authors: Boyes E D , Smith D L
Published: June 2020

The spatial resolution of data in the SEM depends on the the original probe size of the instrument, the beam-specimen interaction volume and the signal escape range. The first two terms are strong functions of the beam voltage. The range [R] of the beam-specimen interaction for chemical microanalysis by x-ray spectroscopy [EDX] has a general dependence given by R ∝ E05/3. The data in Fig.1 were obtained in plan view with a beam at normal incidence using evaporated thin films of aluminum [Z=13] of various thicknesses on a silicon substrate of similar atomic number [Z=14]. The voltage at which the film and the substrate contribute equally to the [EDX] x-ray spectrum [Fig.2] can be measured with an accuracy of only a few volts. The experiment was designed to measure the depth of the interaction volume. In this geometry the data are independent of the probe size which makes a substantial contribution to the lateral resolution of analysis with a simple SEM operated at low voltages [E0 <5kV].
The Characterization Of Organic Charge Transfer Superconductors By Microreflectance Spectroscopy
Authors: Hill S. L. , Krishnan K. , Ferraro J. R.
Published: June 2020

Certain classes of organic charge-transfer salts demonstrate superconducting behavior at liquid helium temperatures. Single crystal x-ray diffraction and infrared microreflectance analysis have been performed on several conducting systems to associate the nature of the crystalline structure with the electrical conductivity. The infrared spectrum for a single crystal salt exhibits absorptions which correlate with superconducting behavior.

DiscussionWilliams and coworkers have performed x-ray Crystallography experiments to demonstrate the presence of an anion cavity between radical cation stacks- of bis(ethylenedithio)- tetrathiafulvalene (ET). The sulfur…sulfur interstack distance in a beta or kappa phase salt assumes a value less than the Vanderwaals distance and exhibit a superconducting (two dimensional) metal behavior (verified by Fermi surface calculations) at 1-20K. The structures of alpha and beta phase ET2I3suggest the potential for several potential intermolecular interaction modes. It may be observed that the beta phase permits both interstack as well as H … X anionic interactions, whereas these interactions are less likely to occur in the alpha phase.
Effects of Transient Neutrophil Influx on the Ultrastructural Morphology of Secretory Cells and Intraepithelial Mucosubstances in Canine Bronchi
Authors: Harkema Jack R. , Hotchkiss Jon A. , Muggenburg Bruce A.
Published: June 2020

Respiratory airway inflammation is often characterized by increased production and secretion of mucus from surface epithelium and by infiltration of airway lumens by inflammatory leukocytes (i.e. neutrophils). Both inflammatory exudation and hypersecretion of airway mucus are thought to be important factors in the pathogenesis of several obstructive pulmonary diseases, including chronic bronchitis and cystic fibrosis. To better understand the pathogenesis of inflammatory airway disorders, it is important to determine what changes in the mucus-secretory apparatus are due to the induced inflammatory process and what changes are due to the inhaled bacteria, toxicant, or other etiologic agent. We previously demonstrated that transepithelial migration of neutrophils elicits a transient depletion of mucosubstances stored in the nasal respiratory epithelium of the rat. This result suggested that neutrophil migration stimulates hypersecretion of mucus from nasal airway secretory cells. The purpose of the present study was to determine whether a transient neutrophi1-influx in the distal intrapulmonary bronchi will elicit a similar hypersecretory response of airway mucus.
Complementary Molecular Information on Phthalocyanine Compounds Derived From Laser Microprobe Mass Spectrometry and Micro-Raman Spectroscopy
Authors: Fletcher Robert A. , Etz Edgar S.
Published: June 2020

Various metal phthalocyanines (Pc's) have come under study because of their optoelectric properties which make them attractive materials for fabrication of ultra-fast molecular electronic devices. Probably the most extensively investigated metal Pc is vanadyl phthalocyanine, VOPc, which has been proposed as a medium for optical storage devices and has been shown to be a photoconductor in the infrared. Several methods have been used to elucidate the relationship between molecular structure and the Pc's optical and electronic properties.

The thrust of this work is to show how well laser microprobe mass spectrometry (LAMMS) and micro-Raman spectroscopy complement each other to provide information so that structural assignments can be made. The vibrational frequencies obtained from micro-Raman spectroscopy indicate molecular structure while mass spectrometry provides the mass (m/z) of the molecule along with certain features of the structure through the fragmentation process. The compounds studied are the metal-free Pc (H2PC), and the derivatives containing the divalent cations of Ni, Cu, and VO. Some of the results are illustrated here for VOPc.
Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe
Authors: Soni K.K. , Williams D.B. , Chabala J.M. , Levi-Setti R. , Newbury D.E.
Published: June 2020

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.

In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.
Design for an Ultraclean, Computer-Controlled Freeze Dryer For Biological Specimens
Authors: Flenniken Robert , Kopf David , LeFurgey Ann , Ingram Peter
Published: June 2020

Electron probe x-ray microanalysis (EPXMA) requires accurate and consistent preparation of samples in order to obtain meaningful quantitative data. For biological systems it is critical that the morphological state and elemental content of individual subcellular compartments are preserved, particularly in the case of cryofixed tissue in which the cryosectioned sample is dehydrated prior to microanalysis.

In dehydrating samples several difficulties are encountered: (1) contamination from the vacuum system used in the process, (2) exposure to warm, humid room air during transfers between instruments, and (3) lack of control over temperature changes of the specimen stage and, therefore, the specimen. While it is possible to circumvent these problems by performing the dehydration in the column of the microscope, it is an inefficient use of the microscope when one freeze drying cycle may exceed 24 hours.

A design for a freeze drying instrument has been developed which reduces the above negative effects and frees the microscope for EPXMA.
Ion localization in Cells by Electron Probe X-Ray Microanalysis (Epxma) Depends on Cryopreparation
Authors: Zierold Karl
Published: June 2020

Elements in biological cells can be localized by EPXMA. The most attractive approach of this method with respect to detection limit and spatial resolution is scanning transmission electron microscopy combined with energy dispersive x ray microanalysis of ultrathin (approximately 100 nm thick) freeze-dried cryosections. The detection limit, here determined by scanning an electron beam of 1.3 nA for 2 min over freeze-dried cryosections from frozen standard solutions was found to be about 10 mMol/kg dry weight for all elements with the atomic number Z higher than 12. Due to the Be window in the x ray detector the detection limit was 20 mMol/kg dry weight for Mg (Z = 12) and 30 mMol/kg dry weight for Na (Z = 11). The lateral analytical resolution was less than 50 nm, limited by section thickness. In most cells 10 mMol/kg dry weight correspond to an absolute detection limit of .500 atoms within a volume of 100×50×50 nm3.
Loss of Elements From Anhydrously Fixed Pollen During Thin Sectioning
Authors: Skilnyk Hilary R. , Lott John N.A.
Published: June 2020

Anhydrous fixations are not commonly considered as a means of preparing biological specimens for energy-dispersive x-ray analysis (EDX). Cucurbita maxima and Cucurbita andreana pollen grains were fixed anhydrously because water-soluble materials such as potassium phytate are extracted by aqueous fixatives. Combining anhydrous fixation with anhydrous sectioning techniques demonstrated significant reduction in the extraction of K, Mg and P from globoid particles in the tube cell cytoplasm in pollen.

Air-dried Cucurbita maxima and Cucurbita andreana pollen grains were fixed for 4h in 2% paraformaldehyde dissolved in pure glycerol (W/V). Samples were washed for 1.5 h in (1:1) glycerol: 100% ethanol mixture. Dehydration began at 95% ethanol because glycerol is hygroscopic and not completely anhydrous. Infiltration was carried out beginning with propylene oxide followed by a series of Spurr’s resin: propylene oxide mixtures which consisted of 1:3, 1:2, 1:1, 2:1, and 3:1 proportions that were followed by three changes of 100% resin.
X-Ray Microanalysis of the Intestine: Identification of Electrolyte Secreting Cells
Authors: von Zglinicki Thomas , Roomans Godfried M.
Published: June 2020

Frozen dried cryosections of mouse jejunum were investigated. Besides Paneth and Goblet cells, two different types of crypt enterocytes could be distinguished according to clearly different electrolyte concentrations and to the presence (type A) or absence (type B) of small secretion granula in the cytoplasm.

Secretion was stimulated by an intraperitoneal injection of either isoproterenol or pilocarpine. In some experiments, isoproterenol stimulation was blocked by alloxan, a potent inhibitor of the adenylate cyclase. Changes of cytoplasmic element concentrations were measured in frozen dried cryosections. In addition, the water content of the cells was measured by fully quantitative bulk specimen x-ray microanalysis.

It was expected that actively secreting cells should display a decrease of Cl concentrations. This behaviour was confirmed in crypt A cells exclusively (Fig. 1). Therefore, it was concluded that crypt A cells are the main secretory cells in the intestinal epithelium.

The water content of all epithelial cells in the intestine was found to increase under pilocarpine stimulation and to decrease under isoproterenol stimulation (Fig. 2).