Antoni van Leeuwenhoek showed the practical use of the light microscope in the 1600s after much effort to improve the quality of optical lenses. Pioneering microscopists such as Ernst Abbé, Hermann Ludwig Ferdinand von Helmholtz, Lord John Rayleigh, Carl Zeiss, and August Köhler then brought us to the brink of optimal performance of the light microscope approximately a century ago, Ernst Ruska and Max Knoll showed in the 1930s that high-energy electrons could be used in place of light, giving greatly improved resolution. In the 1970's Albert Crewe and co-workers developed the scanning transmission electron microscope (STEM) and used the Z-contrast method to improve resolution in the electron microscope by about a factor of two. The scanning probe (nonoptical) microscopes aside, there hasn't been a significant advance in spatial resolution since.

Imaging of sub-micron , sub-surface features of thick optically dense materials at high resolution has always been a difficult and/or time consuming task in materials research. For the most part this role has been relegated to technologically complex and expensive instrumentation having highly penetrating radiation, such as the synchrotron- based Scanning Transmission X-ray Microscope (STXM) or involves the careful preparation of thin cross-section slices for study using the Transmission/Scanning Transmission Electron Microscope (TEM/STEM).

The combination of electron tomography (three-dimensional reconstruction of an individual object from a series of EM tilt images) and elemental mapping (based on element-specific differences in interaction between the primary electron beam and the specimen) is at the very beginning of its application. This article reviews the first published results and considers some requirements and potential uses in biology, employing two examples from our own exploratory work.

The method for creating pseudocolor in Photoshop can be done in few steps, but the image will not be colored in the conventional way. The conventional means for producing pseudocolor comes by using a look up table (LUT). This LUT is an overlay for making a range of colors according to choices provided by the software. The colors are matched to levels of brightness and darkness in the image (grayscale pixel values), typically from a short to long wavelengths. In that scenario, violet colors are matched to the black and near-black pixels and red to those dose to absolute white. Blue, yellow, green and orange become the mid-range pixel values.

LEO's field emission scanning electron microscopes are all based an the “GEMINI” principle as shown in figure 1. In order to reduce aberrations and sensitivity to interfering stray-fields the electron optical column possesses a positively biased booster that shifts the energy of the primary electrons. The incident beam is focussed by a combination of a magnetic lens with an axial gap that avoids field leakage to the specimen and an electrostatic retarding lens formed by the beam booster together with the grounded pole piece cap. Shortly before the electrons hit the specimen they are decelerated down to the desired primary energy.

As it is in traditional materials science, microscopy is a central tool for morphology characterization in combinatorial and high-throughput (C&HT) materials research. Indeed, micrographs are naturally amenable to C&HT studies, since they enable rapid visual screening and automated quantitative analysis by a plethora of well-tested image processing routines. In this article, we present a custom-built and cost-effective automated optical microscopy (AOM) platform designed for the C&HT analysis of gradient specimens. Gradient specimens progressively vary one or more parameters with position, presenting a multitude of experimental conditions within a single sample (see Part 1 of this series).

Ancient forests comprised an enormous biomass and typically flourished in lowland habitats that offered favorable conditions for fossllization, so it is not surprising that petrified wood is the most abundant terrestrial fossil. Petrifaction of wood by carbonates, sulfides, oxides, and phosphates is evidence that fossilization can occur under diverse geochemical conditions, but silicification is by far the most common process.

Transmission electron microscopy (TEM) continues to play an important role in diagnostic surgical pathology, particularly in such areas as kidney pathology and tumor diagnosis, among others. Diagnostic TEM is subject to unique time constraints, quality control regulations, and other problems not seen in other TEM applications. The diagnostic TEM laboratory must produce high-quality electron microscopy on small samples which frequently are suboptirnal in fixation and tissue quality due to the pathology involved and time factors associated with biopsy and surgery.

The traditional polarizing microscope equipped with crossed linear polarizers shows a picture in which the image contrast of a birefringent object depends on both the amount of relative retardation induced by the object and the orientation of its principal axis. For example, if the orientation of the principal axis is parallel to one of the polarizers, then the birefringent object becomes invisible. For best visibility, the principal axis must be oriented at 45° to the polarizers. In addition, the image intensity of the object is proportional to the square of the sine of the relative phase shift between the ordinary and the extraordinary ray passing through the object. The addition of a waveplate as compensator to the optical train provides the opportunity to improve the contrast and measure the relative retardation, but the principal restrictions of orientation dependence and non-linear image contrast remains.

Fluorescence labeling techniques are quite useful to microscopists. Not only can fluorescent probes label sub-cellular structures with a high degree of specificity, they can also do so with a very high degree of sensitivity. This combination of specificity and sensitivity permits observations of cellular events that are not always visible using traditional methodologies, such as brightfield microscopy.

In spite of its relatively small population, about 20 million people, Australia has, across a large number of fields, made significant contributions to science and technology. Expressed statistically, approximately 2.4% of published science research has its origins 'down-under'. Electron microscopy is no exception. Indeed, a significant number of pioneering developments in microscopy (and prominent microscopists) have originated from Australia. For example, early developments in environmental scanning electron microscopy had their birth at this university (through Viv Robinson and Gerry Danilatos) in the 1970's. Leading figures such as David Cockayne, John Cowley, John Spence. Michael O'Keefe once (still?) called Australia home.

Since Microsoft PowerPoint has become the dominant scientific meeting presentation format, my collection of right-left stereo slide pairs has basically been rendered obsolete. Yet, contained within these striking images are valuable scientific data. This communication describes an easy method whereby analog slide data (i.e. scanning electron micrograph RL pairs, Figs. 1 & 2) are transformed into an electronic format such that the need for projector polarizers is replaced by inexpensive red-green or red-blue 3-D glasses.

Replicas of botanical surfaces are sometimes preferred for imaging in the SEM, instead of original surfaces, in cases where it is not possible or desirable, for a variety of reasons, to prepare originais using conventional techniques (chemical fixation followed by dehydration and critical point drying, freeze drying, or cryo-SEM). Samples may be rare (herbarium specimens), or impossible to bring into the lab for processing, and field replication may be the only alternative.

A previous article documented the health hazards associated with embedding media. This article will present specific measures that can be taken to diminish and/or eliminate problems when handling embedding media. Use of personal protective equipment is essential in all laboratory activities and especially when working with embedding media.