Author: Foresight Editor

from the molectronics dept.
Using a scanning electron probe, a research team led by Cees Dekker of the Delft University of Technology in the Netherlands has imaged the undulations of electron waves in carbon nanotubes. In addition to illuminating basic properties of electron conduction in nanotubes, their results also confirm theoretical predictions that electrons in metallic nanotubes moved along two different electron "bands" that can interfere with each other. A member of the research team said it may be possible to manipulate these electrons to make them interfere with each other and create a circuit. The work was reported in the 9 August 2001 issue of Nature.
Additional details are available on the Nature website, and from an article from the Nature Science Update website.

Dekker and his research team also reported in July 2001 that they had created a single-electron transistor (SET) made from a single carbon nanotube,

from the complex-molecular-machines dept.
A collaborative team from the Howard Hughes Medical Institute (HHMI) and Memorial Sloan-Kettering Cancer Center have produced the first detailed images of a protein that performs the crucial task of detecting and repairing broken strands of DNA. The images show that the protein is constructed to cradle DNA while the DNA is repaired and rejoined with great precision. A brief report appears on the HHMI website, and a research paper appeared in the 9 August 2001 issue of Nature.

The work reveals that the protein complex forms a ring that encircles and ìcradlesî the end of the strand of DNA. The scientists speculate that protein complexes on two broken ends of a DNA strand link to one another to hold the two ends in position for joining the DNA back together. They also found that the repair protein does not bind with the DNA bases, but rather grasps the sugar backbone of the DNA strand ó meaning that the protein does not ìcareî about the sequence of the DNA that it binds. The scientists also have evidence that proteins hold the DNA in precise alignment to allow re-joining by repair enzymes.

from the tinkering-with-molecular-machines dept.
An interesting article in the New York Times ("Scientists Are Starting to Add Letters to Life's Alphabet", by A. Pollack, 24 July 2001) describes attempts by researchers to modify the machinery of living systems to product novel proteins that use amino acids other than the twenty or so standard ones used by terrestrial biology. As the article puts it:
"Scientists are taking the first steps toward creating alternative life forms — organisms that use a genetic code different from the one used by all other creatures on earth . . . Such organisms, bacteria to start with, would have novel chemical units in their DNA and synthetic building blocks in their proteins. Scientists hope that such organisms can be used to study biochemical processes in new ways and to produce new medical or electronic materials that cannot now be made by living things."

Note: Access to the NYT website is free, but may require registration.