Having read John Kiernan's contribution in the January 1999 issue of Microscopy Today, I decided to add my two-cents worth (ignoring inflation), I have water-mounted preparations older than 5 years with no indications of threats to their permanence. The procedure is so simple it hardly bears writing about much less printing it for others to read.

I simply make sure any aqueous coversiip preparation on a microscope slide be dry at the edges of an otherwise full (of water) coverslip preparation, I simply add tiny amounts of water to completely fill the space between slide and coversiip, then wait a minute or two for the excess water on the slide outside the coversiip to evaporate. I can speed this step by wicking any excessive excess into a forceps-held small square of filter paper.

Confocal microscopy is a collection of optical techniques that are applied in a variety of hardware configurations. Design strategies for the application of these techniques have generally used laser light (Pawley, 1990). In most laboratories, basic research use has employed laser light in conjunction with a fluorescent substrate to generate an optical signal, either through direct application of a fluorescent material to cells or by the stimulation of a chromophore associated with an antibody which will identify a cellular protein under some specified experimental conditions, The use of confocal microscopy in this type of situation generally requires a standard research microscope, and the tissue may be situated on a slide or other type of container that will provide a stable, controlled environment.

The major factor in light microscopy limiting resolution in practice is not so much the wavelength of light and the resolving power of microscope optics, but the scattering of iight by the specimen. This extraneous scattered light interferes with the light used to image the specimen, effectively reducing the contrast of the imaging light and causing other annoying problems, There have been several inventions dedicated to solving this problem: various forms of interference-based microscopies, confocal microscopy, and most recently, multi-photon confocal microscopy.

The compound microscope forms images in two stages. The objective (first stage) projects a real image of the specimen into the intermediate image plane (IIP) of the microscope at a ratio of magnification (M). The resolution in the IIP is typically between 40 and 100 line pairs permillimeter (Ip/mm). Since the resolution of the human eye is of the order of 5 Ip/mm, additional virtual magnification (V) by the eyepiece (second stage) is necessary to match the resolution of the eye to that of the microscope. The total microscope magnification (VTOTAL) is the product of W x V. The designation VTOTAL is used because the eye views a virtual image in the microscope.

Careful analysis of the composition of the titanium alloys is a very critical part of the overall quality control of all components in modern jet aircraft engines. The engine manufacturing industry is seriously striving for a zero defect rate, which is a very difficult goal indeed. This control is made more difficult by the very reactive nature of titanium when it is heated to its melting point. Titanium reacts with the nitrogen and oxygen in the air to form brittle refractory compounds, so it must be melted and refined in a vacuum. Once these refractories are formed they are very difficult to find or remove and they form the basis for brittle zones in the alloy that can be the initiation site for cracks under the high stress loads found in a jet engine. The presence of nitrogen, in particular, causes a defect called a "hard-aipha", which is an area of nitrogen enrichment containing three to eight percent nitrogen and having a hardness three times that of the alloy.

Modern microscopy allows the life scientist to produce seductively beautiful images with powerful techniques developed by brilliant physical optical scientists, and yet be nearly completely confused with regard to the importance of the results. This is because modern microscopes are something like Lotus race cars: they have all the performance to fly in the hands of an experienced user, or crash and burn spectacularly in the hands of a novice. There is therefore great need for a comprehensive and accurate but accessible "drivers manual" for modern microscopical techniques.

Processes at real interfaces, such as drug dissolution, corrosion, enzyme activity and surfactant structure can now be studied with nanometer resolution using dynamic force microscopy. Optimal sensitivity is achieved when the tip is excited by direct application of a driving force using magnetic methods.

When silicon samples are thinned and backlit, they display a series of colors; from deep red in the thicker (-5-10 μm) regions, to orange and yellow in thinner regions, to effectively transparent in the thinnest regions, This colorful effect can be used as a technique for monitoring the thickness of cross-sectional samples prepared for transmission electron microscopy (TEM).

As seen in Figure 1, a cross-sectional TEM sample of a thin, indium tin oxide (ITO) film on glass was being investigated, A sample was prepared for low-angle ion milling by the Barna method with the addition of an adjacent piece of silicon for a thickness indicator. The colors of silicon could then be monitored to indicate when the ITO/glass sample was thin enough for TEM examination. In the figure, the arrow indicates the region of interest on the ITO/glass sample. This figure was produced by photographing the entire TEM sample through an optical microscope, backlit with a standard quartzhalogen illuminator.

Driven by the analytical needs of microelectronics, magnetic media and micro-fabrication industries, focused ion beam (FIB) systems are now capable of milling and manipulating samples for the analysis of microstructure features having dimensions of 180 nm or less, A technique for locating and extracting site specific specimens for examination by transmission electron microscopy (TEM) has been developed. An identified feature can be located and precisely milled with an FIB system from two sides to prepare an ultrathin sample, and then extracted from the region with a glass rod micromanipulator onto a grid for TEM analysis. This specimen preparation method has been applied to semiconductor failure analysis and to the study of metallic and ceramic microsiructures with irregular topographies and complex mufti-layered components.

With the approach of a new century everyone is getting nostalgic; we just can't resist reflecting on the past and envisioning the future. This struck me with renewed passion on 26 January 1999 when my latest patent (with co-inventor Steven H, Vogel) on a new Confocal Microspectrometer System was issued by the U.S. Patent and Trademark office, What resonated in my mind was the sage advice I received from an admired and distinguished scientist nearly forty years ago, The learned professor opined, "Why do you want to be a microscopist? That's old stuff. No scientific discoveries can be made in microscopy; it is just not a research field. Microscopists never amount to more than glorified technicians". Since then I have seen Professor Dr, J, S, Ploem develop Epf Fluorescence, which revolutionized cytology and expanded the way we think of fluorescence microscopy, I have seen the introduction of the scanning electron microscope, energy dispersive x-ray spectrometers, ESCA, Auger, acoustic microscopes, scanning probe microscopy, confocal microscopy, quantitative image analysis, video-microscopy, FT-IR microspectrometry and many more.

Cover glasses, and by extension mounting media, are the cfe facto front lens of every microscope objective. Those who coverslip are, in effect, completing the assembly of a microscope objective with every cover glass they apply. So while coversliping is a tedious process, its visibly appreciable contribution should not be minimized.

There are optical reasons on which coverslipping do's and don'ts are based. It is optically and physically impossible for alternatives such as liquid substitutes and plastic film to duplicate the specifications and performance of glass cover glasses. Such substitutes are used, however, perhaps because there is so little related useful technical information available to discourage such use.

Orientation Imaging Microscopy (OIM) is a rapid and spatially specific technique for automatically measuring individual crystallographic orientations in a polycrystalline sample. The technique is based on electron backscatter diffraction in the scanning electron microscope (SEM). While the OIM technique has seen many applications to the investigation of structure/ property relationships in polycrystalline materials, with grain sizes ranging from millimeters to submicron, it is not easily applied to the characterization of microstructures at the nanometer scale due to the inherent resolution limitations of the SEM. Thus, a complementary technique for the transmission electron microscope (TEM) would be advantageous for the study of local orientation in submicron structures such as those that exist in nanocrystalline materials and deformed materials.

Applications of scanning force microscopy (SFM) in polymer studies have flourished in this decade, reflecting (a) sensitivity to both structure and properties on the nanometer scale, and (b) ease of operation in ambient environments without sample pretreatment. One drawback in SFM of soft materials has been damage incurred during the imaging process. The problem was alleviated by the development of dynamic force microscopy (DFM) in which the probe spends little or no time in contact with the polymer surface and shear forces are minimized. This mode of operation has been dubbed "tapping", "intermittent contact", "non-contact", "near-contact", etc. As studies proliferated, it became apparent that different researchers were using different terms to refer to the same apparent imaging mechanism, or the same term to refer to different imaging mechanisms.

Questions keep arising regarding safety regulations for storage of alcohol and other flammable liquids in a laboratory. I hope what follows sheds some light on this issue.

Ethanol is classified as a Class IB combustible liquid, Class IB liquids have a maximum allowable container capacity of 20 liters in “metal (non-DOT approved) or approved plastic containers, safety cans or DOT specification metal drums.”

The amount of combustible liquids allowable is determined by the size of the “laboratory unit”. For hospitals with sprinkler systems, per 100 square feet of laboratory space, Class I, II and IIIA (including IB) flammable liquids are limited to 4 L (1.1 gallons) not in approved storage containers or safety cans and 7,5 L (2 gallons) total, including quantities in storage cabinets and safety cans.

Most electron microscopists appreciate that proper operation of the source is vital to the operation of the entire instrument. But because the gun involves a complex interplay of phenomena, few of which can be directly observed, some common misconceptions have gained currency. Typically these myths contain a kernel of truth, but they can also mislead when accepted uncritically. In this series of articles, we explore three areas of common misunderstanding relative to operation of the thermionic (tungsten filament or LaB6) gun. Field emitters are subject to very different considerations.

There are two distinct uses for holey carbon grids: for image checking and for support for ultrathin carbon films for cryo- EM. This procedure gives holes that are too large for convenient image checking, but are the appropriate size for support of carbon films. The procedure is divided into making the formvar mixture, dipping the slides and getting the film on the grids.

1) Take 45 mL of chloroform, add 0.2 g of formvar, and shake to dissolve. A small brawn glass jar with a capacity of 100 mL is the best container to use, and the jars from commercial formvar solution are ideal.

Now you would probably think that I was joking if I were to tell you that there are microscopes made of precious metals, such as silver, rather than brass, and objectives made with diamonds and rubies, rather than glass. But yes, Virginia, prodigal items such as these do actually exist - and not at the end of the rainbow. All right, suppose they do exist, who could afford one? Well, kings for one, Figure 1 shows what is perhaps the most elaborately decorated microscope ever constructed. It was made in 1761 by the wellknown instrument maker George Adams for King George III. George III placed great value on science throughout his long reign, as reflected in his collection of scientific instruments, which can be seen today in the Science Museum at South Kensington in London.

The Interdepartmental Laboratories (IDL) is the core microscopy and scientific visualization research facility for the American Museum of Natural History (AMNH), Its purpose is to operate and maintain facilities that have broad application within the Museum and would be either too costly for the individual research departments to maintain or which would be underused in a typical department setting, The IDL currently maintains two state-of-the-art analytical/imaging microscopes, as well as resources for visualization, webaccessible databases, and networked image scanning, archiving, and printing. The IDL is overseen by Bill Barnett, the IDL Director, and staffed by Angela Klaus, the Laboratory Manager, and David Reddy, the Scientific Visualization and Informatics Manager.