Posted on 04/16/2003 1:13:12 PM PDT by Ernest_at_the_Beach
April 14, 2003 - Ingenious new devices able to see ever tinier, fast-moving objects are providing scientists with striking, 3-D color movies of atoms, molecules and living cells in action.
"We can watch the brain think, develop, age, deal with disease. We can see neurons grow inside the living brain," said Jeff Lichtman, a neurobiologist at the Washington University School of Medicine in St. Louis. "It's like a movie camera."
While biologists use their new instruments to observe cells, chemists use another new technology to track the motions of the infinitesimal particles - electrons, protons and neutrons - that make up an atom. To do so, they use an advanced laser strobe light that slices time into the shortest bits yet achieved, "attoseconds" - a billionth of a billionth of a second.
The technology is like the familiar stop-action photography, freezing a speeding bullet or baseball in flight, but billions of times faster. There are more attoseconds in a minute than there have been minutes since the birth of the universe.
"In attoseconds, we can see electrons move," Richard Loomis, a Washington University chemistry professor, said.
Robert Shull, an expert at the National Institute of Standards and Technology in Gaithersburg, Md., said, "We can count electrons one by one."
On a somewhat larger - but still microscopic - scale, biologists can peer into the nucleus of a living cell and spy on the interaction of proteins, the basic building blocks of every organism. "We're watching the dance of the proteins in action," molecular biologist David Piwnica-Worms, also at Washington University, said.
For example, Douglass Forbes, a biologist at the University of California, San Diego, has made movies of proteins shuttling cargo in and out of the nucleus of a cell through miniature, doughnut-shaped pores. "They're like small spaceships for nuclear transport," Forbes said.
Scientists hope these sensitive new technologies will help detect disease in its earliest stages and develop more effective drugs and treatments.
"We can directly map where a drug goes in the body," Piwnica-Worms said. "We can determine if a patient is drug-resistant or not and tailor his or her therapy to that."
Lichtman's movies of nerve fibers growing in mice reveal a furious competition among several neurons to connect to a target cell. One neuron wins the race and establishes a connection; the others weaken and disconnect.
"These are phenomena that have never been seen before. We are quite excited," he said.
Lichtman said his images show how a brain changes as it learns from experience.
"The nervous system of animals like us is not preordained to do particular tasks," he explained. "We need to learn how to talk, play hopscotch, the violin, et cetera. The way we do this is by selecting among an initial large repertoire of connections. The selection causes some connections to get stronger and the rest to wither away."
Because of the practical as well as scientific value of this research, the federal government plans to invest $850 million this year in the "quest for smallness and speed," said Mihail Roco, head of the administration's National Nanotechnology Initiative. Nanotechnology refers to work with objects ranging in size from one billionth to about 100 billionths of a meter - the realm of atoms and molecules.
These faster, smaller imaging techniques are challenging standard textbook descriptions of how cells work, said Andrew Belmont, a cell biologist at the University of Illinois, Urbana-Champaign.
"Our view has changed the last few years because of our ability to look at living cells," he said. "In the past, we had to tear up cells to study them."
Belmont noted that biologists used to think that the nucleus of a cell was relatively static. Now they can see that its components are constantly moving and shifting in response to signals from its environment. This turbulence might be a clue to the causes of cancer and aging, he said.
I think that Dr Heisenberg weighs in here. Something about uncertainty in Energy times uncertainty in Time is greater than h-bar divided two.
In other words, if you are very certain in time (and dealing in attoseconds, you won't have a clue as to the energy of the electron). You won't know where to find it in energy space.
Call me a skeptic.
Yes, there is. Have you ever wondered how many of the people who are bringing projects like this to fruition are where they are because of affirmative action?
Oh. Sorry.
That was an election suspended in time.
Did find this interesting:
BTW, I think some of the guys that hang out on the drug threads have seen these things.
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