Marek T. Michalewicz writes:
"Dear Nanotechnologists,
At the Spring Foresight Senior Associate Meeting I pledged to give my electronic structure code for public use. Long overdue, but here it is.
I hope the program will be useful to some.
Marek T. Michalewicz
Quantum Precision Instruments Pty. Ltd."
Read more for details on the code and how to access it on the web.
from the Molectronics dept.
The Lucent Bell Laboratories research team that reported they had succeeded in creating transistor with a single molecule channel length in November have published their results in the 7 December 2001 issue of Science ("Field-Effect Modulation of the Conductance of Single Molecules", v294, p 2138-2140). That work was previously reported here on 8 November 2001.
An article in Technology Research News ("Single molecule drives transistor", by Eric Smalley, 12 December 2001) provides some background, as well as some quotes from the researchers.
Brian Wang writes "http://www.aip.org/mgr/png/2001/143.htm TRACKING DNA MOTION WITH PICOMETER ACCURACY. Scientists don't have to settle for averaged results when studying tiny things with x rays. In x-ray diffraction, for example, a crystallized sample with billions of molecules scatters the x rays into a characteristic pattern of spots on a detector which is then decoded to yield lattice structure information. A team of Japanese scientists have developed a method, which they call diffracted x- ray tracking (DXT), in which the bobbing Brownian motion of single nanocrystallites in water are watched by tracking scattered x rays; with this method one acquires information not about the position but the rotary motion of single nanoparticles (Sasaki et al., Physical Review E, September 2000). Now the process has been extended to single DNA molecules, whose Brownian motion can be tracked, for the first time, with a precision of picometers, or 10^-15 m (see figure at http://www.aip.org/mgr/png). The researchers will soon broaden their measurements of important biomolecules. For example, they hope to observe the structural changes accompanying the activation of ion channels in living cells. (Sasaki et al., Physical Review Letters, 10 December 2001; contact Yuji Sasaki, Japan Synchrotron Radiation Research Institute, [email protected], 81-791-58-0831.)"
In a press release (12 December 2001), researchers with MetaPhore Pharmaceuticals, Inc. of St. Louis, MO and the University of Messina (Italy) announced that the companyís artificial enzyme significantly reduced the extent and severity of inflammation and tissue damage to the intestinal wall in an animal model of colitis. The study suggests that MetaPhoreís artificial molecule, which mimics the action of the enzyme superoxide dismutase (SOD), may have potential in the treatment of inflammatory bowel disease (IBD), a group of disorders that cause inflammation or ulceration of the digestive tract.
Previous studies on the use of the artificial enzymes were covered here in July 2001.
An article on the Small Times website ("U.S. government to push nanopores, molecular electronics in next decade", by D. Brown, 13 December 2001) describes two areas of nanotechnology research that will be emphasized by the U.S. National Institute of Standards and Technology (NIST) in it programs:
The Single Molecule Manipulation and Measurement program, launched in late October, will develop new measurement methods using nanopores to probe the structure, function and dynamics of single biomolecules such as DNA and RNA.
The other effort is a new competence-building project in molecular electronics, which uses molecules to perform the function of electronic components. The science is rapidly developing, but it is largely without standards and measurements. The program project will focus on small-ensemble conduction experiments, test structure assessment, electronic structure characterization and conduction modeling in the near term. It will work with several noted university researchers at Yale University, Penn State University and Rice University, the Hewlett-Packard Research Labs and the Naval Research Laboratory.
An interesting and well-written article in the London-based Independent newspaper ("The tiny engines that power life itself ", 17 November 2001) describes studies into the workings of biological molecular motors by researchers at York University and Oxford. In addition to some good explanations of how these biological motors operate, the article shows how studying biological systems may be useful in the design of artificial nanosystems. As one researchers puts it, "If we want to build machines on this scale out of silicon or DNA we need to know the fundamental principles of how they work, and the obvious place to look is nature, which does it so efficiently and elegantly."
The article was also reprinted on the Small Times website.
from the Making-connections dept.
According to a press release (30 November 2001), researchers at the University of California, San Diego (UCSD) Divisions of Biology and Physical Sciences have succeeded in imaging the structural changes between neurons in the brain that many scientists believe take place when human brains store short-term and long-term memories. The images show brain cells forming temporary and permanent connections in response to various stimuli, and provide evidence for how nerve connections in the brain are changed temporarily and permanently by our experiences. Their research results were reported in the 30 November 2001 issue of Cell.
Nick Bostrom writes "I have a new paper, setting forth what I call the 'Simulation Argument'. It's located at http://www.simulation-argument.com
ABSTRACT. This paper argues that at least one of the following propositions is true: (1) the human species is very likely to go extinct before reaching a "posthuman" stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation. It follows that the transhumanist dogma that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation. A number of other consequences of this result are also discussed."
from the intriguing-possibilities dept.
According to a press release, researchers at the University of Houston in Texas have found subtle signs of superconductivity in multi-walled carbon nanotubes (MNTs). The researchers did not see zero resistance in their bundles. They think this is because the connections between the tiny tubes never become superconducting. But they did see more subtle signs of superconductivity within the tubes themselves. The work is preliminary, and other possible explanations need to be eliminated.
A pair of reports in the 21 November 2001 issue of Technology Research News (TRN) Magazine, provide some interesting examples of the many different approaches being pursued to develop nanoscale devices and tools.
The first ("Spot of gold makes tiny transistor", by Chhavi Sachdev) describes work by researchers from Sweden and Denmark at Lund University who have found a way to use carbon nanotubes as electronic leads that connect a circuit with a tiny particle of gold to form a single-electron transistor (SET).
The second ("Chemists create nano toolkit", by Eric Smalley) describes work by a team of researchers at the National Institute for Materials Science in Japan and the Communications Research Laboratory in Japan has come up with a kind of toolkit for building structures out of ring-shaped porphyrin molecules. But, as the article points out, "creating tiny structures is only half the game . . . The researchers also need to make the structures do something, like conduct electricity or convert light signals to electric signals. But even if the porphyrin molecules were not useful by themselves they could be augmented by other atoms or molecules."
