As reviewed in this column on previous occasions, the atomic force microscope (AFM) is steadily making headway as an instrument that can make important contributions to biologic observations. Although the AFM is capable of operating in an aqueous environment, relatively little use has been made of this property to examine cellular structures under conditions that resemble those in vivo. A breakthrough in this regard was recently made by Stefan Schneider, Kumudesh Sritharan, John Geibel, Hans Oberleithner, and Bhanu Jena. of Yale University and the University of Würzburg.

In my 20 plus years of experience, I have found that nearly every specimen contaminates to some degree (some slower, some faster) in an electron microscope regardless of the manufacturer. Most of this contamination comes from the specimen, and it's magnitude is a function of the sample (metallic, semiconductor, organic, etc.), the method of preparation (electrochemical chemical, microtoming, ion milling, etc.), the microscope conditions, the probe and probe current - plus a number of less well controlled factors. Reactive gas plasmas can fortunately be used to mitigate the contamination process and frequently reduce the problem to negligible levels. Basically, one places the specimen/stage in a “tow energy plasma” where the gas acts like a catalyst for a localized surface chemical reaction, The energy of the plasma breaks weak bonds of the hydrocarbon compounds on the surface which then make these species somewhat volatile so that they can further react with the gas in the plasma.

As the dawn of the next millennium approaches, the light microscope enters its fifth century of use, while the personal computer barely enters its third decade.

When Antony van Leeuwenhoek peered through his self made hand crafted microscope and documented the first observations of bacteria and cells, much of microbiology and cell biology was born. When the personal computer became a tool in modern science, molecular cell biologists were well into the age of human genetic engineering.

While the rise and acceptance into scientific importance of the microscope and the personal computer represent vastly different periods of sophistication in modem science, the combination of these two important scientific tools for computer aided microscopy (CAM) clearly provides bold uncharted potentials and opportunities for medicine, biomedical research, and industry in the future century to come.

The current imaging trend in optical microscopy, scanning electron microscopy (SEM) or transmission electron microscopy (TEM) is to record all data digitally. Most manufacturers currently market digital acquisition systems with their microscope packages. The advantages of digital acquisition include: almost instant viewing of the data as a high-quality positive image (a major benefit when compared to TEM images recorded onto film, where one must wait until after the microscope session to develop the images); the ability to readily quantify features in the images and measure intensities; and extremely compact storage (removable 5.25” storage devices which now can hold up to several gigabytes of data).

Hexamethyltiisilizane (HMDS) is an excellent method of chemical drying of hydrated specimens. There are several variables involved in its use, the most easily controlled being the number of transitional steps from 100% eihanol (EtOH) to 100% HMDS and the drying temperature.

Fixation and dehydration are the same for both HMDS and CPD. Once thespecimenisinthefinal 100% ethanol, it must then be transferred to 100% HMDS through a graded series of ethanol-HMDS mixtures.

Grain size characterization in Aluminum alloys can be correlated with thermo-mechanical processing properties. In order to predict the processing characteristics of these alloys under certain combinations of strain, deformation and temperature, the metallographic measure of the grain size can be used. Most of the technigues that have been proposed so far do not provide reliable and reproducible quantitative metallographic measurements of the grain size due to human error. Considering that this manual task is also tedious to perform, a general color image analysis algorithm is proposed to automate the characterization process using an optical microscope with polarized light. This algorithm was tested on several ingots and on rolled aluminum samples. The results show robustness in several conditions, even when the grains can barely be seen by a human operator Other image analysis techniques have been proposed but where judged too slow or too complex, particularly when gathering data over several fields. Time constraints specific to industrial seffings were taken into account when implementing a new algorithm.