The code for the human genome is essentially complete, opening an expansive book about our biologic composition. But the problem is to read this book. The font size is very small, What you are reading now is 9 point font, and genetic information would correspond to approximately 10-50 point font, six orders of magnitude smaller. There are methods to derive genetic information, but recently Adam Woolley, Chantal Guillemette, Chin-Li Cheung, David Housman, and Charles Lieber have developed an elegant way to directly read genetic information with a microscope. The microscope they used was an atomic force microscope (AFM) that employed a single-walled carbon nanotube as its probe.

The programmable array microscope (PAM) is a powerful tool combining the capabilities of nearly all previously described optical sectioning techniques in a single microscope. Not only can the user create optical sections of threedimensional objects, but the PAM's unique adaptive optical strategy allows a user to select the best sectioning method for a particular sample or experimental need. The key to the PAM is a spatial light modulator (SLM). This device, when placed in the image plane of a microscope, can be used to create optical sectioning, generate spatial encoding masks, and/or define regions of interest.

The colors that one sees when looking at a mineral or gemstone are due to the response of that person's eye to the energies of the light, the emission spectrum of the illumination, and, most importantly, physical phenomena in the material that cause some colors to be absorbed while others are undisturbed or enhanced. It is beyond the scope of this article to do more than touch on the physiology of the eye that allows us to see colors. Likewise, we will not dwell on the emission spectra of various light sources. Rather, we will concentrate on the various ways in which materials, especially minerals and their heights of perfection, gemstones, produce color from white light.

We've used gelled agarose to cover & hold monolayer cells in place when treatment leads to cell lifting. Low-gelling temperature agarose (Type VII) (Sigma A 4018 or A 0701) can be made as a 2% stock solution in “phosphate-buffered saline” (PBS) (boiled then kept at 42° C to remain liquid). The agarose can be stored at room temperature at this time, but must be boiled and melted again before use.

Various fluorescent stains and vital dyes have been used to identify dead cells in animal tissues and celi lines. In plants, fluorescein diacetate and propidium iodide have been used to label nuclei and to identify necrotic cells in plant protoplasts and 4,6-diamidino-2-phenylindole (DAPI) has been used to mark senescing cells in sections of roots. However, these dyes may be problematic when used with intact plant tissue with well-developed cells walls which may impede dye penetration. Endogenous fluorescence has been used to identify dead cells in intact and sectioned plant tissues. Published procedures typically employ ultraviolet (UV) excitation wavelengths of 340-380 nm and emission wavelengths of 400- 425 nm, thus requiring a UV filter set.

Some may have read my previous articles in Microscopy Today and know that I am a strong proponent of digital imaging for photomicrographs and photomacrographs. I require that the digital images match the resolution and field size of traditional film images, with the 4X5 Polaroid film most commonly used in metallurgical laboratories where I worked before early retirement. My development of an affordable universal student microscope for home microscopy resulted in a need for color digital images that would meet my requirements at an affordable cost. This need was met by recording on 35 mm film with subsequent scanning of selected film images to a Kodak Master Photo CD. More recently I purchased a CanoScan FS2710 film scanner for digitizing my family's collection of slides and negatives for saving on CD's.

Many of the SEM specimens which we are asked to deal with are highly three-dimensional non-conductive objects, such as silica beads, pollen grains and spores, small inorganic and organic crystals such as zeolites and drug preparations, starch grains, etc. These often cause severe charging problems which result in all of the familiar and tiresome charge-related image artefacts, such as flare, excessive contrast, specimen movement, and variable scan lines. Charging can also make it very difficult to obtain high-resolution images or do satisfactory analysis.

The synthesis of inorganic materials of a specific size and shape is a key aspect in modern powder technology. During the past two decades, solution-based precipitation reactions have been explored for controlled particle formation. A wide variety of particle shapes, sizes, and compositions has been demonstrated. However, several questions, especially concerning particle nucleation, remain. Some of these questions are currently addressed by investigating precipitate (ex situ) at different reaction stages by means of powder x-ray diffraction (PXRD), scanning (SEM) and transmission electron microscopy (TEM).

Many organisms are mostly soft tissue, with hard bits embedded within them. This includes many invertebrates, and vertebrates with calcified areas in their tissues. This procedure works well for soft-bodied corals which have hard pieces of calcium carbonate (sclerites) embedded in their tissues. It should also work for similar soft-tissue/calcified bits in other animals.

There are two possibilites for plunge freezing in LN2: one is “normal” liquid nitrogen -- as it comes from the dewar, the other is slush nitrogen.

If using liquid nitrogen without slush, then something like isopentane, ethane, or propane (ordinary cooking propane will do) must be used. The caveat is that using these liquid gases is a serious fire and explosion hazard, especially since liquid oxygen forms at liquid nitrogen temperatures, and dissolves into the liquid hydrocarbon. These gases can be used safely (1 have done so) but they take care and understanding of what's happening, and a safe place to dispose of the cryogen.