Fluorescence microscopy has employed mercury arc lamps for decades because of their high power and broad spectrum. Fluorophores and filter sets have been developed around the peaks of the spectrum offered by these lamps. When LEDs first entered the fluorescence microscopy arena, prices were high and output was low, but in recent years there have been significant advancements in LED capabilities for microscopy. This article aims to educate users of fluorescence microscopy about the benefits of LEDs compared to conventional mercury arc lamps.

The discovery by Novoselov and Geim of a simple method to transfer a single atomic layer of carbon from the c-face of graphite to a substrate suitable for measurements of its electrical and optical properties has led to an increased interest in studying and employing two-dimensional model systems. An overview of electron and phonon properties of graphene and their relationship to the one-dimensional form of carbon known as nanotubes can be found in. The unique chemical, mechanical, electrical, and optical properties of graphene lead to its many application possibilities such as: single molecule detectors, high-strength low-weight new materials, design of new semiconductor devices, etc.

Neurons in the central nervous system (CNS) are extensively interconnected, and consequently almost half of the human brain is occupied by wiring in the form of the myelinated axons. Dysfunction and degeneration of these axons can result in profound and permanent disability. Axons are much more complex than simple wires, however. Signal propagation relies on elaborate ultrastructural specializations at the nodes of Ranvier, which are demarcated by gaps between myelin sheaths. As living extensions of neurons, axons also require constant replenishment of metabolites and organelles such as energy-generating mitochondria. Studies of pathogenesis of myelinated axons are often constrained by microscopic complexity that requires nanometer-scale resolution over substantial three-dimensional distances.

Complete casts of the vasculature of organs and tissues are obtained by infusing low viscosity resins into the vasculature and allowing the resin to polymerize. Dissolving away the surrounding tissue with alkali leaves a model of the intricate, three-dimensional distribution of vessels in that tissue, which is not easily obtainable by any other means, and which can then be studied with scanning electron microscopy (SEM), Because well prepared casts appear to faithfully replicate the true vascular anatomy of organs including the dimensions of vessels and details of imprints of the endothelial cells lining their lumens, they must also contain quantitative information about that vasculature.

During the past several years, ASTM Subcommittee E04.14 on Quantitative Metallography has been developing an Image Analysis (I/A) methodology to determine the degree of circularity, roundness or sphericity of graphite nodules in ductile cast iron. In the as-polished condition, ideally the iron nodules should appear as dark circular objects in a light gray matrix, Figure 1. When performing Image Analysis measurements for these types of materials, complex gray image procedures should not be required to properly threshold the images to obtain an acceptable binary image on which to perform the measurements.

Scanning electron microscopy (SEM) can produce striking three-dimensional images of biological cells and tissues with submicron resolution of surface morphology. Such cell surfaces are often complex blends of folds, extrusions, and pockets that may be necessary in the positioning of specific molecules within interaction range of each other. Thus, surface changes can have a spatial control over some molecular functions, and identification of select molecules at distinct morphological locations becomes critical to our understanding of total cell function.

Automated Crystal Orientation Microscopy (ACOM) on a grain specific level has proved to be an invaluable new tool for characterizing polycrystalline materials. It is usually based on scanning facilities using electron diffraction , due to its high sensitivity and spatial resolution, but also attempts have been made which rely upon X-ray or hard synchrotron radiation diffraction. The grain orientations are commonly mapped in pseudo-colors on the scanning grid to construct Crystal Orientation Maps (COM), which represent “images” of the microstructure with the advantage of providing quantitative orientation contrast. In a similar way, misorientations across grain boundaries, Σ values of grain boundaries, or other microstructural characteristics are visualized by mapping the grains in the micrograph with specific colors. The principal objectives are the determination of quantitative, statistically meaningful data sets of crystal orientations, misorientations, the CSL character (Σ) of grain boundaries, local crystal texture (pole figures, ODF, MODF, OCF) and derived entities, phase discrimination and phase identification.

Recently, a highly sensitive imaging mode for, complex, calibrated electrical and spatial measurements was made available to atomic force microscope (AFM) users. Scanning microwave microscopy (SMM), an award-winning AFM mode of operation developed by Agilent Technologies, combines the comprehensive electrical measurement capabilities of a microwave vector network analyzer (VNA) with the nanoscale spatial resolution of an AFM.

A great many filters in common use in astronomy are used in order to improve the resulting optical quality in observations and photographs [1-4]. The majority of these filters are also capable of improving image quality in microscopy and photomicrography. Several instances of this have already been reported in this magazine [5-6]. Some new types of RGB-CCD astro filters have recently been developed for multi-shot techniques [2]. These filters can also be regarded as interesting tools for photomicrography that can maximize the quality of true color imaging based on RGB-splitting and multi-shot techniques. The respective methods and their technical benefit are presented and discussed below.

RGB-splitting and multi-shot techniques are routine tools in some fields of professional studio photography and astronomical photography. They can lead to visible improvements in sharpness, resolution and color balance. To obtain maximum image quality, special multi-shot cameras can be used. These are fitted with a multi-shot sensor that does not require any color filters. Therefore, each pixel is sensitive for all colors and pixel interpolations are not necessary.

In-situ electron microscopy has gained considerable attention in recent years. It provides a “live” view of a material or device under study at various length scales. For example, by heating or cooling a sample one can study structural change at the atomic scale to understand the driving forces and mechanisms of phase transitions. By applying electric and magnetic fields on a ferroelectric or magnetic architecture in operation, one can directly observe how electric and magnetic domains switch, how anions and cations shift their positions, and how spins change their configuration across a domain wall, aiding the development of better electromagnetic devices. In the study of photovoltaic devices and junctions, a major challenge is to directly correlate light-induced electric currents with local structural inhomogeneities and dynamics. Such a capability would allow us to evaluate the performance of individual p-n junctions and to improve optoelectronic efficiency.