The general trend of microscopical investigation in biology from the 1950s to the early 1970s was towards obtaining structural information. This goal initially was met using heavy metal and/or aldehyde fixatives, room temperature dehydration with polar organic liquids, embedding with epoxy and acrylate resins, and thin sectioning at room temperature. By the mid 1970s, a perceptible change occurred in the direction of both light and analytical electron microscopy towards investigation of the chemical reactivity and composition of structures made visible with increasingly better spatial resolution for light and electron microscopes. During the past 25 years there have been considerable innovations in microanalytical techniques, including analytical electron and x-ray microscopy and microanalysis, secondary ion mass spectrometry, laser microprobe mass analysis, the scanning probe microscopies, and confocal/multi-photon microscopy. In addition, cryopreservation and the development of chromophores for visualization of molecular and ionic sites within individual living cells as well as membranes have redefined the goal of microscopical preservation: to stabilize cell structure and composition as they exist in the living state.

It was in October of 1964 when I first used a TEM, it was at the Siemens training school run by their agent Aeon Laboratories. A service engineer (we didn't call them technicians in those days), Robin Willis ran the course, five days for just alignment and cleaning! Robin, by the way, moved to University College London, Anatomy department and became the first person to publish on the tilting of biological samples. He actually invented tomography without knowing it! He used a fish tank within which he hung the negatives of his +60 to -60 tilt series. This procedure created a three dimensional image of the thin section, again I would guess, for the first time.

Time of flight secondary ion mass spectrometry (ToF-SIMS) and scanning electron microscopy (SEM) provide valuable complementary information about the molecular composition and morphology of biological samples, but both techniques are performed under high vacuum, which is not compatible with hydrated samples. Designing a suitable method to prepare biological (hydrated) samples for high vacuum conditions is important to obtain reliable and scientifically meaningful results from ToF-SIMS and SEM and to enable the routine use of these techniques for characterization. This article will compare freeze-drying and critical point drying for preparing adherent and nonadherent cells for ToF-SIMS and SEM analyses.

The analysis was finally completed, the data graphed, and I had to admit to myself, it was looking like an auspicious moment. Only a few weeks earlier, Charlie Lyman and I had been discussing a project that I had been working on for some time, one in which I was admittedly being deliberately vague concerning the details. However, I had promised to keep him updated when it succeeded. Given the date (April 1st) and the data in hand, I couldn't resist sharing with him (and a few colleagues) the first results from that experiment—and my thinly veiled attempt at a quasi-April Fools Day joke. After we exchanged a number of emails that day, Charlie concluded his last message with the line that many of us have heard from both him and Ron Anderson: “A little more text and you can have an article in the July issue of MT.” Have I gotten you curious? Well then read on!

Friedrich Johann Karl Becke (1855-1931) was an Austrian geologist, mineralogist and petrologist from the University of Prague, who developed a method for determining the relationship between light refraction and refractive index differences observed in microscopic specimens. The phenomenon, which is now referred to as the formation of Becke lines, has been named for him. Becke also conducted important work on metamorphic rock recrystallization, and later contributed to the development of a descriptive terminology and classification of mineral assemblages in metamorphic rocks.

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 regards to the purchase of a histology diamond knife for preparing light microscopy sections, I was one of those folks, in possession of a nice glass knife maker, who was very comfortable with breaking, making and using glass knives. So the question was—did I really need a costly diamond knife for making light microscopy sections?

Once I finally tried a diamond histo knife, I never went back to glass. There are some very good incentives for this: long lasting cutting surface, much time saved in sample preparation, larger block faces can be prepared, and more consistent cutting results obtained. A histo diamond knife is also a big aid in preparing specimens for diagnostic or biological microscopy. These very important bonuses make a good list to have in hand when justifying the purchase to your organization. However, are they worth the price? Yes, I think so—even so far as providing each tech with their own diamond histo knife.

It has been in the back of my mind to write this up for MT since I retired from a certain large computer company. Inasmuch as Paul's article above is a perfect lead-in, there is no time like the present. Our lab supported a semiconductor integrated circuit and a ceramic substrate manufacturing facility. We were continually required to measure circuit line widths on plan-view specimens and layer thicknesses on cross-section specimens for both semiconductor and ceramic substrate specimens and we were often asked to determine thin film grain size and ceramic raw material particle size data. A large number of measurements were required for each specimen to guarantee statistically sound data. We had image analysis software available that we used whenever we could, but often found that measuring things on a system using grey-level image analysis as input simply did not work. This is especially true for thin film grain size determination when using diffraction contrast TEM images for input.

As the old adage goes, beauty is in the eye of the beholder. Ultimately, in the world of jewelry, the unwitting buyer uses his or her naked eye to decide which baubles are the most beautiful and worthy of wear. The expert jeweler and gemologist, however, know that each gem is subjected to rigorous scientific examinations and standards to determine its value and authenticity.

As the number of methods for altering gems grows with technology, methods to counteract counterfeiters, who can take a worthless stone and alter it to make it appear like a more expensive gem, are essential to gem buyers and traders. They must be able to detect artificial stones.

Gemologists assess gemstones based on several standards such as chemical composition and purity. Chemical composition plays a significant role in evaluating gems, as two of the same gemstone can differ chemically. One of the most well known methods of non-destructive testing for detecting gem quality is X-ray fluorescence (XRF) spectroscopy. Increasingly in demand, XRF spectroscopy is an ideal technique for fighting the battle against fraud.