We all experience fret now and then, that is, worried, distressed, vexed, or troubled feelings and emotions. Not good.

FRET, by contrast, is not so bad when it stands for fluorescence resonance energy transfer. This occurs when a dye molecule absorbs light of a particular color, transfers the energy to a different dye molecule, which in turn emits light of an altogether new color.

And now thanks to work from the Chemistry Department at the University of Connecticut, we may have a way to use FRET to create something potentially practical: DNA lightbulbs.

Neret al. produced nanofibers of DNA containing the two types of fluorescent dyes and showed that ultraviolet (i.e., colorless) excitation could produce blue, orange, or white emission, depending on the conditions (Angewandte Chemie 48: 28 (9 June 2009), 5134–5138). It turns out that nanofibers are much more efficient (brighter) than simpler DNA films containing the same ingredients. Structure matters.

Why should you care? Suppose all the bazillions of semiconductor LEDs (light emitting diodes) we encounter in everyday existence could be replaced with a purely organic material. Quoting the authors, this possibility “is appealing from the perspective of both environmental disposal and utilization of a renewable resource.”

Green chemistry inches ever closer to reality, one experiment at a time.

By now most readers will have heard about the 9 July Pew Research Center report on the attitudes of Americans on science and scientists. At one level the news is good: Americans hold scientists in high esteem and believe science contributes to our economic well-being.

At another level, though, the Pew report reveals the seeds of future problems: scientists think other folks don’t know enough about science, and all Americans become wary of one another on tender issues like evolution and climate change.

The latter point on ideological division mirrors the way contemporary society deals with all manner of challenges: draw a line in the sand, and line up people on one side or the other. The antidote is to resist the idea that everything can be reduced to simple categorization lacking in nuance, subtlety, and intricacies of understanding.

On the matter of general scientific understanding, you might like to try out the Science Knowledge Quiz administered by Pew as part of the study. My hunch is that anyone who reads Periodic Tabloid would likely achieve 100% correct answers, but take a look for yourself. The survey showed a broad scoring range among the citizenry at large, but please let me know if I’m overestimating how much scientifically educated people actually know.

Moore’s law states that the number of transistors in integrated circuits doubles about every two years. This is why computers keep on getting smaller, why memory chips keep increasing in storage capacity, and why digital cameras keep having more megapixels.

But can Moore’s law hold forever?

Of course not, even though it has held steady for nearly half a century. It’s hard to imagine a transistor being smaller than a single atom, and even Gordon Moore himself has pointed out that exponentials always crash at some point.

The limitation at the moment is the photolithography process that lays down circuit diagrams on silicon chips. Current technology can produce features as small as 45 nanometers. But suppose you could use carbon nanotubes (about tenfold smaller at 4nm in diameter) as the mask for the lithographic process?

You can, at least in principle, thanks to new work from Columbia University chemists. Liu et al. deposited carbon nanotubes on silicon to mask the wafer for etching by hydroxide ions (Journal of the American Chemical Society (2 June 2009), doi: 10.1021/ja903333s). They cajoled the reaction sufficiently to get trenches about 4–6 nanometers deep, but alas ten times as wide.

The authors speculate that the resolution could be improved by clamping down the wandering tendency of the carbon nanotubes through clever chemistry. This would then yield the hoped-for tenfold increase in masking potential over current photolithography.

So Moore’s law may continue to hold for some time to come. With luck, we’ll postpone the inevitable exponential crash just long enough to come up with Moore’s law 2.0.

Who were the most accomplished chemists of the 20th century? Of course such a question is unanswerable in any truly objective way, but that uncertainty doesn’t diminish our interest in speculating about “the answer.”

A couple of engineers at UCLA proposed a methodology for naming the 10 highest achieving physicists for the 20th century prior to World War II (the heyday of modern physics). Their approach is to equate accomplishment with fame, the latter as evidenced by hits on physics Nobel Prize winners in a Google search.

You could surely debate all manner of reasons why this is a wholly bad measurement tool, but the authors do offer some evidence for its veracity. You can check the arguments and the results for yourself, but no doubt you won’t be surprised to see Einstein at the head of the list.

Naturally I wondered about the test being applied to chemists. Here’s the result of the Googleized highest achieving chemists prior to mid-century, starting with number 1: 

1. Marie Curie
2. Fritz Haber
3. Otto Hahn
4. Sir William Ramsey
5. Francis W. Aston
6. Wilhelm Ostwald
7. Emil Fischer
8. Heinrich Wieland
9. Carl Bosch
10. The Svedberg

(For readers who think they know the history of chemistry: for how many of these chemists can you describe their work?)

If you add in the second half of the 20th century, Linus Pauling would break in the list as number 9 and Robert Woodward as number 6. In my book Pauling is in the running for number one, throwing some doubt on the method.

But guess who appears on the top ten lists in both physics and chemistry? Marie Curie, who is also the only woman on either. Go, Marie!