Tiny transistors replaced vacuum tubes as a means of performing the important tasks of switching and amplifying in electronic circuits, but it wasn't until many transistors and other elements could be wired up in a small space that today's information revolution could begin. Integration and miniaturization not only led to more efficient packaging but also to quicker processing since signals travel shorter paths.
The Nobel Prize in Chemistry goes to Alan J. Heeger (University of California, Santa Barbara), Alan G. MacDiarmid (University of Pennsylvania), and Hideki Shirakawa (University of Tsukuba, Japan) for discovering that plastics polymers, modified in certain ways, can conduct electricity very well. From Saran wrap to foam cups, polymers are normally insulating materials, but in the 1970s, Shirakawa, finding a new way to make the polymer polyacetylene, accidentally added 1,000 times too much catalyst. He produced a silvery film, which he later presented in 1977 to Heeger and MacDiarmid, who had been investigating the possibility of "synthetic metals."
The three studied the properties of the material. When they added iodine, the polymer's electrical conductivity shot up by several million times. The result was a whole new field-conducting polymers-which has led to plastic versions of many electronic devices, such as light emitting diodes. Compared to inorganic materials, plastics are more flexible and potentially cheaper and easier to manufacture. In addition, the discovery of conducting polymers provides a foundation for the development of molecular computers, in which electrically conducting molecules act as the building blocks of computing devices.
The 2000 Nobel Prize in Medicine shares a theme similar to the two Nobels awarded today-whereas the physics prize celebrates silicon circuits, and the chemistry prize recognizes plastic circuits, the medicine/physiology prize cites neural circuits, a topic which is of great importance to physicists alongside many other types of scientists. The prize went to Arvid Carlsson (University of Gothenberg, Sweden), Paul Greengard (Rockefeller University), and Eric Kandel (Columbia University) for their discoveries concerning the transmission of chemical signals in the nervous system.
The brain has about 100 billion nerve cells; messages from one cell to another get relayed at in-between points called synapses. The three researchers made discoveries in one type of communication, known as slow synaptic transmission, involving chemical signals that alter nerve cell function for periods ranging from seconds to hours. Carlsson, for one, identified dopamine as a transmitter in the brain and realized its importance for controlling movements; this research has led to drugs for Parkinson's disease.
Understanding signal transmission in the body has become a major area of physics research. For example, chaos researchers have been striving to elucidate and control the electrical patterns that lead to disorders such as epilepsy. In another example, new research shows that the tree-like structures called dendrites, which feed a nerve cell with information, send out stronger signals the farther their distance from the nerve cell's main body, or soma; that's because dendrites lack insulating material and act like leaky wires which must compensate for lost electrical charge.
-Philip P. Schewe, AIP Public Information
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Associate Editor: Jennifer Ouellette