In general terms, parasites that cause malaria are injected into the skin by mosquitoes. They then travel into the bloodstream and then to the liver where they invade liver cells and mature into forms called schizonts. Within each schizont, cell division produces thousands of tiny new forms called merozoites, each of which, when released into the bloodstream, is capable of infecting a red blood cell. This “traditional” pathway for malarial parasites may not be the only way these parasites travel through the body. Using some increasingly more powerful immuno-imaging tools, Rogerio Amino, Sabine Thiberge, Béatrice Martin, Susanna Celli, Spencer Shorte, Friedrich Frischknecht, and Robert Ménard have demonstrated an additional route that could have profound implications for developing effective vaccines for this major worldwide disease.

In the field of document examination, several approaches can be taken to probe the authenticity of a piece of ancient writing. Scholars have the task of analyzing, and possibly translating, the language and content of a document, and assessing the character and quality of the script. Materials characterization plays another role. Both the document substrate and the ink can be examined to determine whether the materials and methods of creation are consistent with those known to be used during the historical period to which the document is attributed.

Since the earliest explorations of the microscopic world in the 17th century and continuing to the present day, microscopists have continuously faced a challenge in that there is an inherent tradeoff between the resolution of the microscope and the size of the field of view--as the resolution of the microscope is increased to resolve smaller features, the observable area of the specimen decreases proportionally. While being a long recognized characteristic of the traditional microscope design, this tradeoff is becoming a significant hindrance as optical microscopes are being used in automated systems for advanced biotech research, medical diagnostics, robotic micromanipulation, and industrial inspection.

In order to get high resolution images from any scanning beam microscope one must be able to produce a sufficiently small probe, have a small interaction volume in the substrate and have an abundance of information-rich particles to collect to create the image. A typical scanning electron microscope is able to meet all of these requirements to some degree. However, a helium ion microscope based on a Gas Field Ion Source (GFIS) has significant advantages over the SEM in all three categories.

Spurr low viscosity embedding medium was introduced in 1969 and used vinyl cyclohexene dioxide (VCD or ERL 4206) as the low viscosity epoxy resin together with nonenyl succinic anhydride (NSA), the flexibilizer DER 736, and the accelerator dimethylaminoethanol (DMAE or S-1). This low viscosity formulation has been used extensively for embedding plant materials, microrganisms and other difficult specimens. Over the years numerous concerns about the toxicity and carcinogenicity of VCD have been raised. VCD (Fig. 1) was finally removed from the market in 2005 and replaced with ERL 4221 (Fig. 2), a cyclic epoxide with a higher molecular weight and higher viscosity. Vendors instructed that ERL 4221 be substituted for VCD at the same rates as used in the original Spurr formulation. This direct substitution resulted in a more viscous resin and blocks were extremely hard and brittle and lacked the sectioning qualities of the original formulation. Vendors then suggested modifications to the dehydration schedule and reductions in the amount of DMAE to improve the quality of the blocks.

When making a sculpture, it is the eyes that guide the hands and tools and perceive the outcome. In simple words, “in order to make, you must be able to see.” So too, when making a nanoelectronic device, it is the microscope (eyes) that guides the process equipment (hands and tools) and perceives the outcome. As we emerge into the century of nanotechnology, it is imperative that the eyes on the nanoworld provide an adequate ability to “see.” We have microscopies that resolve 0.02 nm on a surface (scanning tunneling microscope (STM)) or single atoms in a specimen (atom probe tomographs (APT) and transmission electron microscopes (TEM)).

Just two decades ago, life scientists studied biological structure, developmental anatomy and intracellular processes by describing individual snapshots of kinetic events. Today, with so much bioscience research focusing on dynamic processes that occur on the molecular, cellular and whole organ level, it is important to record events as they happen, over seconds, minutes or hours, in living cells. Photographs and camera lucida drawings of fixed, stained cells have given way to live cell imaging using fluorescent probes, warming trays to promote cell viability and cinemicrography as a method of recording events.

With new image analysis software for infrared spectroscopy, semi-quantitative studies can be performed without the use of standards providing rapid measurements of component concentrations when an approximate value is suitable or when quantitative standards are not available. Infrared spectroscopy has been used for many years to identify the composition of organic and other materials. Single or multi-component samples can be analyzed and their chemical structures determined by comparing their absorbance peaks to known spectral libraries or fundamental molecular transitions. This technique is used throughout the scientific community and provides rich information.

It is common for microscopists to examine fluorescent samples that have been exposed to a mixed set of fluorophores with specific staining properties. Images are often captured from these samples as a set, using different filter sets to isolate specific elements of the sample. Sometimes the images are captured in gray scale, and in other cases, they are captured with color cameras. In either case, one would often like to combine the images to create a single image that presents the information from all fluorophores at once. This kind of display is particularly useful for determining the relative locations of different components.

It is often said that: “…a picture is worth a thousand words… ” This can be certainly true for images from an Atomic Force Microscope.

Although we often know that nanoparticles exist and we have a mental picture of what they look like, it is often helpful to be able to “see” the particles to verify that they are morphologically what we imagine they are. When the particles are much less than a micron in diameter, they cannot be directly visualized with an optical microscope. At best, sub micron particles appear as “diffraction spots” in an optical microscope. It is possible to visualize nanoparticles with SEM or TEM.

Nano-TA is a local thermal analysis technique that combines the high spatial resolution imaging capabilities of atomic force microscopy (AFM) with the ability to obtain understanding of the thermal behaviour of materials with a spatial resolution of sub-100nm. This breakthrough in spatial resolution of thermal analysis, which is ~50× better than previously reported, has profound implications for the fields of polymers and pharmaceuticals where local thermal understanding is key.

The conventional AFM tip is replaced by a special nano-TA probe that has an embedded miniature heater and is controlled by the specially designed nano-TA hardware and software. The nano-TA probe enables a surface to be visualised at nanoscale resolution using the routine imaging modes of AFM. The user is able to select the spatial locations for the investigation of the thermal properties of the surface. Heat is supplied locally via the probe tip and the thermomechanical response is measured.

Traditionally, contamination control in SEMs has focused on pump oils, finger prints, dirty specimens, and good vacuum practice in manufacturing. Now, the use of dry pumps at all stages of the vacuum system of new FE SEMs, and the use of better vacuum practices on the part on users and manufacturers have made environmental hydrocarbons, the hydrocarbon background contamination of our world, a significant source of the remaining hydrocarbons in electron microscope vacuum systems. These environment sources of hydrocarbons (HC) cause a loss of resolution and contrast in imaging at the highest levels of magnification.

Attaching a sample to the instrument's sample stage is commonly the first step in the operation of an AFM. For our commercial Digital Instruments Multimode AFM, a sample is usually attached to a magnetic sample puck by double-sided tape, the sample puck is then placed on the instrument’s magnetic sample stage, and analysis can begin.

The use of double-sided tape, however, has unpleasant consequences. First, the surface of the sample puck becomes quite sticky due to residual glue from the double-sided tape ! removing the sticky glue is not a happy job. One cannot just throw a soiled sample puck away! Second, double-sided tape does not always give satisfactory mechanical stability during AFM operation, especially when high resolution imaging is being carried out. Sometimes the tape-mounted sample will creep slowly, which can cause significant drift of AFM images. This is because the tapes and their adhesive films are made of pressure sensitive materials that tend to change shape when pressure and/or temperature vary.

Excessive light to detectors can be very harmful. Too much light, either monochromatic or wide band, can easily destroy photomultiplier tubes (PMTs). Charge-coupled devices (CCDs) cameras, of modern design, are typically made with cut-outs so that saturation beyond several pixels will cause them to shut off. Unfortunately, the detectors in the back of your eyes do not have automatic shut-off mechanisms, and can be easily destroyed with excessive light.

As a review of filters and cubes, keep in mind that the primary job for the excitation filter is to block all light other than the desired band being used to excite the fluorochrome. The primary job of the emission filter is to block the excitation source. If these two optics are chosen correctly and inserted in the beam path, the only light reaching the detector is the fluorescence emission from the fluorochrome. Nothing from the source should make it to the detector. This very weak emission intensity has no chance of harming the detectors. If these two optics are not perfectly matched, the excitation light may reach the detector and cause all sorts of problems.

Osmium crystals tend to cling to the glass ampoule walls making dissolving them difficult. Smashing the vials results in glass shards that may get into sample vials and can be dangerous, or carry into embedding media and damage diamond knives.

A simple trick to eliminate smashing osmium vials is to dip the sealed ampoule into liquid nitrogen. This releases the osmium crystals from the glass walls. Then simply break the vial using an ampoule cracker (available through EM supply houses) and pour the osmium crystals into a bottle containing the water for the OsO4 solution. Wait a few minutes to let the ampoule warm-up, and it is easy to see if all of the crystals have been dumped out of the ampoule. Let the solution sit overnight at room temperature in a hood and the next day the crystals will be totally dissolved.