It is widely accepted that approximately 65 million years ago, an extraterrestrial object slammed into the Yucatán Peninsula of Mexico, creating a worldwide climatic shift that wiped out the dinosaurs, and many other terrestrial and marine species. But what happened to the insects? They undoubtedly represented a larger biomass than the dinosaurs, but it's fair to say they haven't captured the public's imagination in the same way. The reason the fate of the insects has not been adequately explored is due to the paucity of the available fossil record of the insect bodies. There are a few records of insects embedded in amber or fossilized, but practically none are available from the time of mass extinction referred to as the Cretaceous-Paleocene boundary. Recently, Conrad Labandeira, Kirk Johnson, and Peter Wiif found an ingenious way to examine indirect evidence and show what happened to the insects during this time.

Numerous microscopy techniques, based on both imaging and diffraction, exist for the measurement of grain size distributions in polycrystalline thin-film samples. The accuracy of each technique is affected by three major factors: the effective resolution of the instrument relative to the characteristic grain size, the detection of the grain size through the thickness of the film, and the recognition of boundaries between adjacent grains during post-processing. When the instrument resolution is primarily considered, the measurement technique has a practical grain size measurement range, see Fig. 1 for a comparison of ranges for several measurement techniques. In bulk metallurgy grain size analysis, methodology has been developed to represent 3-dimensionai grain structures from measurements taken on 2-dimensional images.

Photomicrography is the combination of photography and compound microscopy. Photographers working with compound microscopes are facing many challenges (for an introduction see [1] and [2]). Digital photography offers great advantages, but also adds additional difficulties. Digital cameras have been used in photomicrography for over a decade now. Today, we have access to many excellent consumer-grade digital cameras that are most suitable for low-cost imaging systems for light microscopy. In this short paper, I summarize my experience with the Sony DSC-S70 digital camera, which comes with a nice, large Zeiss lens. (Most of the ideas presented in this paper are also valid for the DSC-S75 and DSC-S85.)

The use of electronic files made universally readable in Adobe Acrobat will eventually replace paper submission in nearly every avenue used by scientists, whether files go to grants agencies, to reviewers, to colleagues via e-mail, or to publishers. It's for the obvious reason of reducing paper and the costs of mailing, but also because fonts often misbehave when going across operating system platforms, and because seemingly everyone has the Acrobat Reader, A better understanding of Adobe Acrobat can go a long way toward reducing the frustration that can easily arise from using this program inappropriately and ending up with poor image resolution.

The reliability of the confocai laser-scanning microscope (CLSM) to obtain intensity measurements and quantify fluorescence data is dependent on using a correctly aligned machine that contains a stable laser power. The laser power test appears to be one of the most useful tests to quickly evaluate if a system is misaligned or functioning sub optimally by recording insufficient laser power readings. The test using a power meter can indicate if the system is aligned properly up to the plane of excitation on the stage, or if the machine has a defective component (i.e. a dying laser, or a defective fiber). In our experience, without sufficient power throughput in the system, the PMT voltages will have to be increased to high values to visualize fluorescence derived from specimens, which will introduce reduced image quality. In addition the cause of the decreased laser power may result in other problems i.e. laser instability, loss of axial resolution, and increased noise.

The low-loss electron (LLE) method in the scanning electron microscope (SEM) was proposed by Dennis McMullan in 1953: “…the beam from the specimen could be restricted to the electrons which have lost only small amounts of energy and which have therefore travelled only short distances through the specimen.”

Subsequent studies showed that the LLE method gives different image contrasts from the more familiar secondary electron (SE) method: (i) it is less affected by specimen charging; (ii) has a shallower information depth for a given beam energy; (iii) shows less serious penetration effects at sharp edges; (iv) shows stronger channeling contrast; and (v) Is better for showing shallow surface topography.

Formaldehyde is one of the most rapidly penetrating fixatives used. Unfortunately, it is one of the slowest to fix tissue. This paradox was finally explained by Burnett in 1982. An fine description of the properties of formaldehyde may be found in John Kiernan's book.

The penetration rate of formaldehyde in mm/hr is a variable thing. It depends on how the data is obtained. It may also vary slightly depending on tissue type. The penetration rate of formaldehyde fixatives has been extensively studied, often with conflicting results. The penetration of non-coagulating fixatives is difficult to measure.

K-12 instruction in biology has traditionally taken a very descriptive approach. This is in marked contrast to quantitative as well as qualitative way of looking at things in physics and chemistry. This qualitative/descriptive approach even extends into the iaboratory portion of the biological course. One way to introduce a more quantitative approach is in the microscopy portion of the biology curriculum. Because cellular structure is primarily a microscopic province It makes sense to introduce students to the different microscopic tools such as TEM and SEM, as well as the light microscope that are used to investigate cell structure.

Designing a microscopy and/or analytical instrumentation facility can be completed in a step by step approach, whether it is a completely new facility or an existing one moving into expanded quarters. The procedure is independent of size. The same basic procedure is required for one room or an entire building. There are several major factors that must be taken into consideration. Check lists can be compiled by the microscopist/analyst. One should easily be able to start at any point along the way. The time and effort Initially put into the design will pay for itself many times over in both the convenience and efficiency of the resulting laboratory.