It has been appreciated that many invertebrates have morphologic and/or behavioral traits that help them survive by camouflage for predator avoidance or being stealthy predators themselves. The morphologic features that are involved have been described in greater detail as the technology has evolved. Recently, Rebecca Duncan, Kellar Autumn, and Greta Binford have used dissecting microscopes and scanning electron microscopes (SEM) to reveal new details of how certain species of spiders hide themselves by covering themselves with sand, and how the sand particles tenaciously stick to the spiders’ bodies.

Although considerable advances have been made in Energy Dispersive Detectors for microanalysis, low energy analysis under 1000eV is still relatively poor due to detector response and inefficient production of low energy x-rays. X-ray optics fabrication methods by O’Hara and measurements by McCarthy et. al. indicated that it should be possible to fabricate x-ray optics that could be used to significantly increase the low energy x-ray flux seen by an EDS detector without increasing the beam current. Such an optic would be useful to increase low energy counts without moving the detector closer, which would simply increase the high energy counts and dead time.

Transmission electron microscopy (TEM) has been proven to be one of the most convenient and straight forward methods for resolving sub-nanometer structures. The use of these instruments in life sciences, materials sciences and in the semiconductor industry has contributed greatly to many significant advances. However, typical TEMs are very large, expensive and relatively complicated to operate. Fortunately, recent advances in TEM technology and product design have created a new TEM instrument that is very well suited to everyday applications in hospitals, universities and laboratories of all types. Able to fit in a small room, this new TEM does not require the expensive, extensive building modifications usually associated with a TEM installation.

In order to understand the focusing action of a TEM objective lens, a simple imaging system (figure 1) is best considered. This system consists of an objective lens and a single projector. In operation, the projector is adjusted as required within the total imaging system to achieve a magnification, M2, on the screen. This results in a focal length of F1, with the lens seeking to find an image in the position M1. If the objective lens does not place the image at M1 the result on the screen is an out of focus condition. The objective lens may have produced an image short of M1, overfocus, or beyond M1, underfocus.

When imaging a sample, it is desirable to have the entire area of interest in focus in the acquired image. Typically, microscopes have a limited depth of field (DOF) and this makes the acquisition of such an all-in-focus image difficult. This is a major problem in many microscopic applications and applies equally in the realm of scanning electron microscopy as well. In multifocus fusion, the central idea is to acquire focal information from multiple images at different focal planes and fuse them into one all-in-focus image where all the focal planes appear to be in focus.Large chamber scanning electron microscopes (LC-SEM) are one of the latest members in the SEM family that has found extensive use for nondestructive evaluations. Large objects (~1 meter) can be scanned in micro- or nano-scale using this microscope. An LC-SEM can provide characterization of conductive and non-conductive surfaces with a magnification from 10× to 200,000×. The LC-SEM, as with other SEMs, suffers from the problem of limited DOF making it difficult to inspect a large object while keeping all areas in focus.

In this article, we will describe how nanoscale particles may be individually visualised (but not imaged) in liquids and from which higher resolution particle size distribution profiles can be obtained compared to other light scattering techniques. The method is called Nanoparticle Tracking Analysis (NTA)

Sample preparation is minimal, requiring only dilution with a suitable solvent to an acceptable concentration range (between 10 and 1010 particles per ml depending on sample type). Accurate and reproducible analyses can be obtained from video images of only a few seconds duration and the results allow particle number concentration to be recovered. Given the close to real-time nature of the technique, particle-particle interactions are accessible as is information about sample aggregation and dissemination. All particle types can be measured and in any solvent type providing that the particles scatter sufficient light to be visible (i.e. are not indexed matched).

Metamorphic rocks formed under conditions of high temperature (>600°C) and high lithological pressure (>1 GPa) and being subject to a subsequent tectonic uplift commonly include a remarkable number of fascinating mineral textures. One type of these well known and extensively described high-grade metamorphic textures are the so-called corona structures or reaction rims which, by definition, are primarily based on metamorphic reactions that cause the formation of concentric layers of new mineral phases separating an older and unstable mineral core from a newer and equally unstable mineral matrix. In other words, corona structures in metamorphic rocks preserve evidence of changes in the environmental conditions (temperature, pressure, fugacity of H2O) experienced by the rock during its tectonometamorphic history.

In photomicrography, two fundamental problems often arise in practice: The higher the magnification and the higher the thickness or three dimensional extension of the specimen, the lower is the depth of focus which can result in parts of the specimen being indistinct. The larger the area of the specimen, the lower is the resolution in images showing the specimen in a total view. Additional problems will occur, when the lowest magnification of the respective microscope is not low enough for inclusion of the specimen’s total size so that only parts of the specimen will be visible in photo micrographic images. Table 1 presents the focal depth and lateral resolution of microscopic objectives with regard to their magnification and numerical aperture (modified from [4] and [7]).

The intricate relationship between molecular structure and function is a common theme in molecular biology. Visualizing the structure of biological macromolecules through imaging is therefore useful in understanding their varied biological roles. The process is often complex; imaging in a high voltage Transmission Electron Microscope (TEM) involves extensive staining and freezing. The aim of this experiment was to image DNA easily in a close to natural environment in a simple microscope. Samples were imaged using a Leo (Zeiss) 1550 Scanning Electron Microscope (SEM) with a Schottky field emitter in the 15-30kV range to reduce radiation damage. After imaging off-the-shelf DNA, two more DNA samples were dialyzed with RbCl and NaCl and imaged to elucidate what made the DNA visible.

The scanning electron microscope (SEM) is commonly used to obtain images of a wide variety of samples within a wide range of magnification factors from the order of 10 up to about 105×. This technique is usually applied, but not limited to, the investigation of conductive samples. This is because the interaction of the scanning beam with the sample generates a net charge on the sample surface. Thus, if the sample is conductive, the charge can be quickly disposed of to ground, away from the beam spot. If the sample in non-conductive, the sample becomes locally charged, giving rise to a distortion of the primary beam. In certain conditions, the charge stored on the sample is able to reflect back the incoming electrons, much like an electrostatic mirror.

Zoysia, a common turf grass, is characterized by the presence of functional salt glands. These glands are specialized structures through which the plants excrete excess salt. Research on the mechanism of salt secretion in Zoysia matrella (Manila grass) prompted the development of a specimen preparation technique that would preserve the secreted salt and salt gland. Conventional aqueous preparative techniques wash away the secreted salt on the leaf surface. A specimen preparation technique was modified from a simple cryo-preparative technique for examining hydrogels in the transmission electron microscope.

The fact that the machinery is “behind the wall” or out of sight may mean that it is not being looked after as well as it should. Do you have a regular schedule to check the vacuum pumps and accessories in your microscopy lab, or do you wait till it fails? Do you keep a service record of the repairs done to your vacuum pumps and the vacuum levels measured after each service? In a department where there are instruments that last ten years or more and the operators and technicians regularly change it makes good sense to keep a record of the vacuum pumps oil changes, service and performance.