How do lumens form? Two mechanisms that come readily to mind are a wrapping model, similar to the wrapping of the myelin sheath around a neuronal process, and a solid core of cells followed by apoptosis of the central cells. Another obvious mechanism that was suggested over 100 years ago is the fusion of intracellular vacuoles. Whereas several recent studies have supported this latter mechanism, it has not yet been proven. Now, the appropriate animal model (zebrafish), the modern techniques (transgenic chimeras), dyes (green fluorescent protein and monomeric red fluorescent protein) that can be linked to proteins to label vacuoles, and two-photon imaging in real time finally have provided the strongest support yet. In an article by Makoto Kamei, Brian Saunders, Kayla Bayless, Louis Dye, George Davis, and Brant Weinstein the assembly of endothelial tubes from intracellular vacuoles was observed in vitro and in vivo.

In 1965, Gordon Moore predicted that the number of components in an integrated circuit would double every year. The drive for higher performance with greater economy has been a major factor in the pursuit of Moore's Law. Device scaling is expected to continue without interruption, and products manufactured using a nominal 22nm feature size should become commercially available by the year 2011. This article will detail the technology enablers that make Moore's Law possible, and the improvements in microscopy techniques required to meet the challenges that Moore's Law presents.

For many years, as long ago as 1872, the Amphipleura pellucida (Ap) diatom striae and punctae have been an intense object for measuring the quality of resolution of the light microscope (LM). More recent publications have also referenced Ap and the difficulty of resolving its punctae. Thus, from 1872 to 1947,much attention was directed towards Ap but without paying much attention to its detailed valve structure. This was probably due to lack of resolution of LM to reveal the details for the Ap punctae (pores). Work by Stoermer and Pankratz did TEM analysis of Ap in 1964. While their results and mine do not agree, this could be attributed to specimen preparation and the source of the diatoms. However, there is an heretofore unresolved issue about the physical differences of Ap from different geographic locations. My current work should resolve this issue. This started as a challenge about whether Ap could be selectively oriented inside up or inside down.

As engineering challenges grow in the ever-shrinking world of nano-design, methods of making dynamic measurements of nano-materials and systems become more important. The Doppler electron velocimeter (DEV) is a new measurement concept motivated by the increasing importance of nano-dynamics. Nano-dynamics is defined in this context as any phenomenon that causes a dynamically changing phase in an electron beam, and includes traditional mechanical motion, as well as additional phenomena including changing magnetic and electric fields. The DEV is only a theoretical device at this point. This article highlights the importance of pursuing nano-dynamics and presents a case that the electron microscope and its associated optics are a viable test bed to develop this new measurement tool.

As nearly all imaging has moved from analogue media such as photographic film into digital image files it has become vital to understand how resolution and digital sampling affect the information contained in these images. This article is a basic introduction to the important concepts and how they should be applied, using general assumptions, rather than a rigorous mathematical approach. The focus is on optical microscopy although the essentials are the same for any digital imaging. The basic concepts are explained with reference to optical microscopy, but then the article moves on to more general aspects of sampling in digital imaging. More detailed, and mathematical, treatments can be found in a range of literature but a particularly detailed and instructive description can be found in Chapter 4, Handbook of Biological Confocal Microscopy, 3rd edition, Ed J.B. Pawley, Springer 2006.

In addition to other determining factors, the optical quality of images is strongly dependent on the quality of the lenses and the spectral characteristics of the incident light in light microscopy as well as in astronomy. Chromatic aberration is one of the most important reasons for limitations of the hotgraphic quality. Ideal lenses that are completely free from such aberrations do not exist. A little chromatic aberration remains in “high-end” apochromatic lenses. Moreover, several lenses for special applications, e.g. microscopic objectives for long focal distances and thick glass plates or objectives with an integrated iris diaphragm for observations in dark field, are mostly not apochromatically corrected because of their optical compromises.

Since the pioneering mineralogical and crystallographic studies of the 1960s and 1970s it has been regarded as a fundamental tenant of earth sciences that the growth of minerals, and especially of magmatic mineral phases, depends upon the physico-chemical state of the growth environment. Meanwhile, based on extensive empirical and experimental approaches, some factors controlling crystal growth and, as a consequence of that, crystal shape or morphology can be detected and documented. Therefore, the chemistry and temperature of the growth environment, as well as its content of volatile phases, have been found to be key to understanding the crystallization processes.

No longer are biologists content to peer through the oculars of a microscope. Eyes have been replaced by digital cameras. Instead of manual control of microscope stages, filters and light sources, modern microscopes have become fully robotic. Image acquisition and robotic movements require computer control. With such equipment it is possible to automatically record images at multiple wavelengths, carry out time-lapse recordings of living cells using very short exposure times and low light doses, and even to record images at multiple positions (e.g. from a multi-well plate) without operator intervention. Clearly, computer control of light microscope image acquisition is making many new experimental imaging strategies possible in the biological sciences.

The Microscopy and Imaging Center at Texas A&M University is a multi-user facility involved with preparation and analysis of many different biological and materials sciences projects. Vapor stabilization and coating is an important part of our specimen preparation methodology for difficult biological and materials, especially polymer, samples. The procedure for all our vapor preparation techniques is done in a simple, economical apparatus set up in a properly functioning fume hood with a flow rate of at least 100 ft/min (Fig. 1). The apparatus is made from a glass petri dish or a glass petri dish for the bottom and an appropriate size beaker for the top. Specimens, mounted on stubs, are placed inside the chamber and the fixative (osmium tetroxide, ruthenium tetroxide or acrolein) is placed in a small container (plastic bottle cap) near the specimens.

The first demonstration of an SEM to students is a rewarding experience. Whether it is the beginning of a course in instrumentation or just an illustration of the abilities of an SEM for “prospective users”, whether students have engineering or biological backgrounds, both graduate and undergraduate students are thrilled to see a “real electron microscope”. We thus have an easy task of only having to choose the right specimens to fulfill their anticipation and to present the right amount of information that will be easily absorbed and remembered for a long time.

Insects are the prima donnas of SEM imaging. We usually start our demonstrations with insects (Fig.1). Their multifaceted eyes, terrifying (at proper magnifications) mouths, exoskeletons, jointed limbs, and segmented bodies look so astonishingly alien under the microscope, so remarkably different from their familiar (to the naked eye) appearance, that insects unfailingly get the students thrilled and prepare them to absorb information.

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?

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.