Recently, a question popped up on the Microscopy mailing list (http://www.microscopy.com) regarding the use of CCD cameras in a TEM that can be summarized as “why use a 4 megapixel camera instead of simply magnifying twice as much and use a 1 megapixel camera?” One of the assumptions was that the computer screen used to display the image only has so many pixels anyway (usually in the order of one megapixel), that even printers could not print out the image in sufficient resolution, and that stretching the image to render all available pixels would “change the magnification”.

It is our experience that these things can be confusing to beginning microscopists and casual users of an instrument, and this was confirmed by several people on the mailing list. So, how best to explain the concepts “magnification” and “resolution”, which beginners often consider interchangable?

In case you didn't realize it, one of the things that is important about a business plan is to have an enthusiastic champion. I don't know if I've seen a person that has represented what she does more enthusiastically than Elaine did just now.

One of the reasons why I asked Elaine to go first was there's a lot of preparatory work that goes in place before you put together a business plan. Elaine did a very nice job in planning, and one of the key things in her Strategic Plan was that she took planning and made it a part of the business plan. A “S.W.O.T.” Analysis is an exercise that you go through when you are dealing with an enterprise that talks about Strengths, Weaknesses, Opportunities and Threats. Elaine put together the S.W.O.T. Analysis in addition to the current facility description and wish lists and that was extremely helpful in putting together her business plan.

Semi-thin sections don't always want to stick to glass slides, but subbing slides is usually not needed. For sections about 2 μm thick and no larger than 4 mm on a slide, this simple method works well for me:

1. 1) Clean 1x3 inch glass slides with an ethanol rinse, then air dry at room temperature or blow down with a hair dryer.

2. 2) Collect sections on a drop or two of distilled water on the slide, transferred there from the microtome with a clean fine tipped artists brush. Collect about 8-12 sections per drop.

3. 3) Warm the slide beneath the water drop from below using an alcohol lamp, fairly hot, but not to boil, of course. After drying by heating the sections stick quite well.

4. 4) Stain, usually with 0.2 μm filtered toluidine blue, again heating but gently this time, for about a minute, until stain “develops” the section.

5. 5) Rinse that stain off with distilled water from a squirt bottle, even directing the spray right onto the sections to get rid of any precipitate. Dry again gently with flame.

The heating is the trick. There should not be any need for subbing or otherwise treating slides other than cleaning them.

This work involves the development and application of a database for the morphological, crystallographic, and chemical characterization of amphibole particles that occur as accessory minerals in the former vermiculite mine in Libby, Montana. The data in the database were collected using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) techniques for particle-by-particle characterization of mixed mineral dust samples.

In the fall of 1999, public attention was focused on the small town of Libby due to health concerns over potential amphibole asbestos exposure that occurred in the now closed vermiculite mine. The vermiculite deposit, located in the Rainy Creek Igneous Complex, about seven miles northeast of Libby, was discovered in 1913 and commercial production of vermiculite began in 1923.

One of the most important tasks of microscopy is to provide information about structures in their natural state. Since most life science microscopy procedures require fixation, dehydration, drying, and sectioning, diverse artefacts are unavoidable. It is also possible to dehydrate the water content of a specimen by freeze-drying. However, even relatively stable surface structures are changed during such treatments. Methods of liquid substitution and freezing-substitution show good results for biological specimens with a waxy solid coverage (Ensikat and Barthlott, 1993) and soft specimens in a mechanically deformed state (Gorb et al., 2000).

However, all these methods have certain restrictions for some types of specimens. For example, there are numerous biological surfaces covered with secretory fluids. Some specimens bear solid waxy coverings, which can be partly dissolved and washed out in organic solvents, such as ethanol, acetone, or propylenoxide. Often one would like to visualise dynamic processes (growth, deformation, or crystallisation) under environmental conditions, but at the high resolution in the SEM.

Diesel Particulate Filters (DPFs) are designed to capture exhaust particulates from engines. The filter material collects the particulates deep in the substrate (deep-bed filtration) before transitioning to other filtration methods on the surface. The deep-bed filtration has been characterized by modeling studies but little experimental information about the particulate, or soot, penetration in the filter material is available. Traditional evaluation methods do not provide sufficient contrast between the soot and mounting resins.

Due to the difficulty of locating carbon soot in the pores in these filters, ultra-thin section techniques (under 10-micron-thick sections) were used for the characterization of these samples. Under transmitted light, the carbon soot is black because it blocks the light, and the carbon in the resin material is relatively clear.

Nanoparticles (1-10 nm in diameter) are particularly susceptible to disorder, amorphization, deformation and/or dissolution upon ion irradiation as compared to their bulk counterparts, which is a consequence of the enhanced surface area to volume ratio of the former (structural disorder is often observed to be preferentially located at the surface). Synchrotron-radiation-based analytical techniques are ideally suited for the elucidation of structural perturbations as compared to the bulk material. Such techniques are commonly complemented by cross-sectional transmission electron microscopy (XTEM). XTEM offers invaluable information with respect to shape and morphology of the nanoparticles.

For the present work, Cu nanoparticles were synthesized within a 2 μm amorphous SiO2 matrix on a 520 μm Si support by ion implantation and thermal annealing following a procedure described elsewhere. In order to study the influence that ion irradiation has on the nanoparticles, the sample was then irradiated with 1x1015 ions / cm2 high-energy (5 MeV) Sn+ ions.

A Duke University Talent Identification Program (TIP) nanotechnology course curriculum integrated a Hitachi TM-1000 table top scanning electron microscope (SEM) into the classroom to excite and educate gifted and talented high school students interested in this emerging field of research. Students learned about synthesis, characterization and applications of nanotechnologies to encourage them to begin thinking about why and how properties of matter change at the nanoscale. The syllabus was created to introduce fundamental concepts like introductory quantum mechanics, atomic bonding, allotropes of carbon and applications including nanomedicine, nanoelectronics, nano-textiles, bionanotechnology and nanometals. The classroom environment allowed students to take intellectual risks and the course content was presented through a variety of methods to utilize the Kolb learning model and encompass intellectual, personal, social and practical learning methods. The teaching approaches employed traditional principle based lectures, but also included guest speakers, experiential learning activities and both project or problem based learning laboratories.

Colloid and adsorption physics are a very complicated business and often have a lot of surprises. In 1991 Kramarcy and Sealock published a paper in JHC Vol. 39, No. 1,pp. 37-39, 1991: “Commercial Preparations of Colloidal Gold-Antibody Complexes Frequently Contain Free Active Antibody”. Their data indicate that proteins adsorbed onto colloidal particles of 5nm and larger can dissociate from the particle surface with time and that, at times even shortly after manufacturing, colloidal gold reagents may contain free binding molecules. This is not necessarily the result of bad manufacturing practice, as adsorption and desorption are in equilibrium at all times. Some proteins (there are even variations between antibodies from different animal species) are more liable to become dissociated than others, and the conditions of coupling play a role as well.

It can be difficult to get an even layer of metal coating when sputter coating a sample with steep sides, a rounded lower surface, or one that doesn't make complete contact with the surface of the specimen stub. It can be particularly difficult to get sputtered metal in under the sample, and so an insulating sample (like most polymers and biological specimens) may have little or no electrical path to ground. This results in charging, and increased chances of specimen heating and beam damage in the SEM.

These stub holders were made to fix that problem. A couple of metal shelf brackets, which slide into pegs and support the shelf, were modified. The brackets are small 90° angles with a hole in one face and a peg on the other face. To modify them, first the 90° angle of the bracket is bent slightly past 90°.

The monitoring of performance of an SEM in a multi-user facility is a difficult task as user feedback is generally not reliable. Regular quality control measurements must be undertaken using standard conditions to maintain research-quality products. The test specimens should also be available to the general user community to allow them to monitor their own skills against the reference images. The ready availability of these specimens also helps to eliminate problems related to user specimen preparation, as users can refer back to them when in doubt with respect to SEM performance.

Certified SEM imaging standards are expensive and cannot be provided routinely, particularly where a number of SEM are present. We have investigated a range of potential materials and preparations in search of a low cost, reliable and robust specimen for use in routine (day-to-day) quality control.

Resolution and pixel number is a recurring question in microscopy, especially in regards to appreciating or visualizing the image's resolution once an image is captured. For instance, what is the effect of changing a one megapixel camera for a three megapixel camera? It is important to consider nanometers (or micrometers) per pixel, which will determine the ultimate resolution available. Of course Nyquist will tell you that you can't push things to the single-pixel dimensions—a couple of pixels is more likely the limit.

It is also important to remember that raw pixel count alone is meaningless. The image formation process must be considered. The camera needs to be matched to the phosphor for optimum cost and performance.

I was pleased to see the article describing some of the history of the Florida Microscopy Society in a recent issue of Microscopy Today. I have since learned that many regional microscopy societies are busy not only archiving their history but retelling it to the next generation of microscopists. I think this is important. The Southeastern Microscopy Society (SEMS) has had a historian since its early days. I am the current historian and I view my job not just as someone who archives the records but also the one responsible for preserving the human face of our history. This includes telling our story. The Southeastern Microscopy Society's Newsletter, The BEAM (http://www.southeasternmicroscopy.org/beam/beam.html) has a regular history feature, where established microscopists recount interesting experiences in the laboratory, memorable SEMS' meetings, or other aspects of the personal side of science.

Nanowires or porous films grown on a substrate normally lack mechanical strength, and may be subject to damage during specimen preparation. When we made cross-sectional TEM specimen for this type of sample, we modified the traditional method by covering the sample with epoxy to improve the film strength, and applying single-section ion milling to protect the film from over-milling.

The sample surface is first covered with G1 epoxy. We choose G1 for this application because it is relatively thick and cures at low temperature. For samples with a dense-growth of nanowires or a thick porous film, a brief moment in vacuum helps to get rid of the air bubbles in the epoxy. The glue is cured at 100 degree C for 10 minutes, until its color turns to a reddish brown. To remove the excess glue and flatten the surface, the sample is then ground and polished until the glue is less than 0.1 mm thick.

Is there's a child in your life? Are you thinking about giving a microscope this holiday season? DO IT! But please think carefully about what you buy. You’re reading Microscopy Today, so you use some sort of microscope professionally; you may be tempted to give the youngster a lab-quality hand-me-down. DON’T! The complexities that you take for granted will only intimidate them. The youngest child will enjoy a magnifiying glass. I still remember the pocket-flashlight-style microscope that I had when I was young; I took it everywhere. After that, the best “first” microscope is a monocular dissecting scope; you can consider a very basic compound microscope later, in the middle school years.

I have found the best way to cleave [001]-oriented silicon wafers is rather different compared to GaAs or InP. The problem is that Si prefers to cleave on (111) planes rather than (110) and so one gets an angled face with the cleave, which is usually rather uneven and often doesn't run straight. This is even worse when cleaving close to an existing edge, which attracts the crack front as it propagates. Good for making low-angle cleaved specimens, but a problem otherwise. It is possible to make Si cleave on (110) by cleaving the wafer without any support.