This issue marks the beginning of the 15th year of publication for Microscopy and Microanalysis (MAM), and it is my pleasure and honor to start my tenure as Editor-in-Chief of the journal with Volume 15, 2009. The idea for this scientific journal originated during Charles Lyman's term as president of the Microscopy Society of America in 1991, and in 1992 a peer-reviewed demonstration issue was published as vol. 22, no. 1 of the MSA Bulletin. After evaluating several publishing formats, a new peer-reviewed journal was launched in 1995 as the Journal of the Microscopy Society of America. When Springer-Verlag became the publisher in 1997, the title of the journal was changed to Microscopy and Microanalysis. In 2002, publication moved to Cambridge University Press (CUP) and in 2006 the CUP Managing Editor, Ed Barnas, and the MAM Editor-in-Chief, Charles Lyman, moved manuscript submission for the journal to the electronic submission site “Manuscript Central” operated by ScholarOne. At the end of 2008, Charles Lyman retired from the journal having served as MAM Editor for 12 years and Editor-in-Chief for 9 years.

2008 marked the 40th anniversary of the seminal paper “Solid-State Energy-Dispersion Spectrometer for Electron-Microprobe X-ray Analysis” by Ray Fitzgerald, Klaus Kiel, and Kurt Heinrich [Science (1968), 159, 528] that introduced the Si(Li) energy dispersive spectrometer (EDS) detector as a practical analytical tool to the electron microscope community. In recognition of that anniversary, the Microscopy Society of America and the Microbeam Analysis Society organized a symposium at the 2008 Microscopy and Microanalysis Conference in Albuquerque, New Mexico to review the remarkable progress in Si(Li) EDS that has made elemental analysis available on virtually any electron beam platform.

Dynamic characterization techniques have been utilized in the fields of biology, chemistry, physics, and materials science for many years. Techniques range from neutron scattering to X-ray diffraction. Two of the fields experiencing much development recently have been electron-based techniques. Namely, ultrafast electron diffraction (UED) and ultrafast electron microscopy (UEM) have been advancing rapidly, but unfortunately, in parallel. We are approaching an era where the convergence of these two techniques could open up a wide range of scientific and technological opportunities and advancements.

Electron channeling effects can create measurable signal intensity variations in all product signals that result from the scattering of the electron beam within a crystalline specimen. Of particular interest to the X-ray microanalyst are any variations that occur within the characteristic X-ray signal that are not directly related to a specimen composition variation. Many studies have documented the effect of crystallographic orientation on the local X-ray yield; however, the vast majority of these studies were carried out on thin foil specimens examined in transmission. Only a few studies have addressed these effects in bulk specimen materials, and these analyses were generally carried out at common scanning electron microscope microanalysis overvoltages (>1.5). At these overvoltage levels, the anomalous transmission effect is weak. As a result, the effect of electron channeling on the characteristic X-ray signal intensity has traditionally been overlooked in the field of quantitative electron probe microanalysis. The present work will demonstrate that electron channeling can produce X-ray variations of up to 26%, between intensity maxima and minima, in low overvoltage X-ray microanalyses of bulk specimens. Intensity variations of this magnitude will significantly impact the accuracy of qualitative and quantitative X-ray microanalyses at low overvoltage on engineering structural materials.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

While electron cryotomography (ECT) provides “molecular” resolution, three-dimensional images of unique biological specimens, sample crowdedness, and/or resolution limitations can make it difficult to identify specific macromolecular components. Here we used a 1.4 nm Nanogold® cluster specifically attached to the Fc fragment of IgG to monitor its interaction with the neonatal Fc receptor (FcRn), a membrane-bound receptor that transports IgG across cells in acidic intracellular vesicles. ECT was used to image complexes formed by Nanogold-labeled Fc bound to FcRn attached to the outer surface of synthetic liposomes. In the resulting three-dimensional reconstructions, 1.4 nm Nanogold particles were distributed predominantly along the interfaces where 2:1 FcRn-Fc complexes bridged adjacent lipid bilayers. These results demonstrate that the 1.4 nm Nanogold cluster is visible in tomograms of typically thick samples (∼250 nm) recorded with defocuses appropriate for large macromolecules and is thus an effective marker.

The large macro- and microscopic variability in kidney morphology among fish makes it difficult to build a “universal” understanding on its function and structure. Species-specific studies are thus needed. Thus, morphological study of brown trout trunk kidney was performed, considering potential seasonal and gender effects.

Osteocytes are surrounded by hard bone matrix, and it has not been possible previously to directly observe the in situ architecture of osteocyte morphology in bone. Electron microscope tomography, however, is a technique that has the unique potential to provide three-dimensional (3D) visualization of cellular ultrastructure. This approach is based on reconstruction of 3D volumes from a tilt series of electron micrographs of cells, and resolution at the nanometer level has been achieved. We applied electron microscope tomography to thick sections of silver-stained osteocytes in bone using a Hitachi H-3000 ultra-high voltage electron microscope equipped with a 360° tilt specimen holder, at an accelerating voltage of 2 MeV. Osteocytes with numerous processes and branches were clearly seen in the serial tilt series acquired from 3-μm-thick sections. Reconstruction of young osteocytes showed the 3D topographic morphology of the cell body and processes at high resolution. This morphological data on osteocytes should provide useful information to those who study osteocyte physiology and the several models used to explain their mechanosensory properties.

On February 2, 1968, R. Fitzgerald, K. Keil, and K.F.J. Heinrich published a seminal paper in Science (159, 528–530) in which they described a solid-state Si(Li) energy dispersive spectrometer (EDS) for electron probe microanalysis (EPMA) with, initially, a resolution of 600 eV. This resolution was much improved over previous attempts to use either gas-filled proportional counters or solid-state devices for EDS to detect X-rays and was sufficient, for the first time, to make EDS a practically useful technique. It ushered in a new era not only in EPMA, but also in scanning electron microscopy, analytical transmission electron microscopy, X-ray fluorescence analysis, and X-ray diffraction. EDS offers many advantages over wavelength-dispersive crystal spectrometers, e.g., it has no moving parts, covers the entire X-ray energy range of interest to EPMA, there is no defocusing over relatively large distances across the sample, and, of particular interest to those who analyze complex minerals consisting of many elements, all X-ray lines are detected quickly and simultaneously.

The melanocortin 5 receptor (MC5R) is a G-protein coupled receptor (GPCR) with a typical seventransmembrane-domain structure. It is assumed that all GPCRs undergo several post-transcriptional modifications during synthesis and folding until finally target to the cell membrane. The available information about the specific domains responsible for the correct targeting of the melanocortin receptors to the cell surface is scarce. Regarding MC5R, it was shown that the first 20 aminoacids of the human receptor can be deleted without affecting the ligand binding affinity, but further deletions of the N terminus resulted in total loss of binding. These results were not directly correlated with the cell surface expression levels of the receptor. Thus, we aim to define the specific MC5R domains important to its correct trafficking and signaling, and preliminary results are here presented.

Tannin-based rigid foams of different bulk densities and their carbonized counterparts were investigated for the first time by X-ray microtomography. This method allowed acquisition of three-dimensional pictures of such highly porous materials. Through mathematical treatment of the images, extremely useful physical characteristics such as porosity, fraction of open cells, connectivity, tortuosity, and pore-size distribution were determined as a function of the foam's density. The obtained information was compared with independent data derived from pycnometry measurements and scanning electron microscope image analysis. The agreement was shown to be acceptable in the limit of the accuracy of the laboratory microtomograph (4 μm). Moreover, recalculating properties like permeability were shown to be quite possible based on the results of standard microtomography data.

With the advent of silicon drift X-ray detectors, a range of new geometries has become possible in electron optical columns. Because of their compact size, these detectors can potentially achieve high geometrical collection efficiencies; however, using traditional approximations detector solid angle calculations rapidly break down and at times can yield nonphysical values. In this article we present generalized formulas that can be used to calculate the variation in detection solid angle for contemporary Si(Li) as well as new silicon drift configurations.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Ultrastructure of the zona pellucida (ZP) of canine and feline oocytes has not been fully investigated. The objective of the study was to evaluate the potential use of the low vacuum scanning electron microscope (LVSEM) with oocytes. This required development of a method to prepare canine and feline cumulus-oocyte complexes (COCs) for LVSEM to provide ultrastructural information on the ZP. COCs were collected from ovaries, and cumulus cells were either partially or completely removed to reveal the ZP. COCs and zona-intact oocytes were fixed at 4°C for 1 h in 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.4 and subsequently viewed wet or further processed by critical point drying, and viewed uncoated or sputter coated with gold. Although the spongy surface of the ZP was visible at low vacuum in uncoated oocytes, coated oocytes had more details at high vacuum. The ZP surface of canine and feline oocytes contained numerous various-sized, spherical or elliptical pores that narrowed centripetally splitting into several smaller, deep pores. The round to oblong cumulus cells tightly surrounded the ZP. Each corona radiata cumulus cell tapered into a thin projection that entered the ZP. Our detailed techniques will enable future studies connecting ultrastructural and molecular aspects of oocyte maturation and development in mammals.

Microscopic images of hair from 36 individuals were evaluated for color (using the CIE L*a*b* color space), hair thickness, and the pattern of pigmentation. These measurements were compared to each other and to reflective spectrophotometric measurements of macroscopic hair color. Three areas on three strands of hair were examined for each individual. Despite a large ΔE* value, there is a strong relationship between macroscopic and microscopic L* values that would be useful if one was trying to predict the color of a head of hair (macroscopic) from a strand (microscopic). A relationship between hair lightness (L*) and thickness is also found at both the macroscopic and microscopic levels. The information acquired in this study may be useful to those conducting a microscopic examination of hair, especially in forensic science, as well as those researchers investigating macroscopic hair color and hair morphology for the purposes of forensic science, anthropology, and medical science. Further investigation into objectively measuring and quantifying the microscopic color and properties of hair will assist in increasing its validity as evidence in forensic casework.

Extrapolating from a brief survey of the literature, we outline a vision for the future development of time-resolved electron probe instruments that could offer levels of performance and flexibility that push the limits of physical possibility. This includes a discussion of the electron beam parameters (brightness and emittance) that limit performance, the identification of a dimensionless invariant figure of merit for pulsed electron guns (the number of electrons per lateral coherence area, per pulse), and calculations of how this figure of merit determines the trade-off of spatial against temporal resolution for different imaging modes. Modern photonics' ability to control its fundamental particles at the quantum level, while enjoying extreme flexibility and a very large variety of operating modes, is held up as an example and a goal. We argue that this goal may be approached by combining ideas already in the literature, suggesting the need for large-scale collaborative development of next-generation time-resolved instruments.

We present a fast and simple method to prepare specimens for transmission electron microscopy studies of oxide thin films deposited on silicon substrates. The method consists of scratching the film surface using a pointed diamond tip, in a special manner. Small and thin fragments are then detached from the film and its substrate. Depending on the scratching direction, the fragments can be used for plan-view or cross-section imaging. High-resolution images can be also obtained from thin edges of the film fragments. The method is demonstrated in the case of HfO2 sol-gel films deposited on [100] Si wafer substrates.