Health

Analysis: Talc-based cosmetics test positive for asbestos

Laboratory tests of talc-based cosmetics products, commissioned by the Environmental Working Group, found asbestos—a deadly human carcinogen for which there is no safe level of exposure—in almost 15 percent of samples.

Genetics

Q&A: Getting to the roots of fragile X syndrome

The cause of fragile X syndrome (FXS), the most common inherited intellectual disability, is easy to see in the lab. Under electron microscopy, an affected X chromosome exhibits a deformed tip that gives the disorder its ...

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Electron microscope

An electron microscope is a type of microscope that uses a particle beam of electrons to illuminate a specimen and create a highly-magnified image. Electron microscopes have much greater resolving power than light microscopes that use electromagnetic radiation and can obtain much higher magnifications of up to 2 million times, while the best light microscopes are limited to magnifications of 2000 times. Both electron and light microscopes have resolution limitations, imposed by the wavelength of the radiation they use. The greater resolution and magnification of the electron microscope is because the wavelength of an electron; its de Broglie wavelength is much smaller than that of a photon of visible light.

The electron microscope uses electrostatic and electromagnetic lenses in forming the image by controlling the electron beam to focus it at a specific plane relative to the specimen. This manner is similar to how a light microscope uses glass lenses to focus light on or through a specimen to form an image.

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