What would you expect to find if you pointed your Web browser to www.chemistry.com? The Chemical Heritage Foundation, perhaps. The American Chemical Society would be another good guess. Or you might anticipate a random site devoted to the wonders and mysteries of chemical science.

Go ahead, give it a try (simply click the link above). I’ll wait….

Were you surprised to find yourself at a dating site?

My own reaction is thoroughly schizophrenic. On the one hand, romance is often spoken of as having the “right chemistry,” and close relationships are similarly described as resulting from “good chemistry.”

But I also think the appropriation of chemistry for this purpose is yet another indication of the crude commercialization of everything that has lasting or enduring value.

If you find yourself distressed, disappointed, angry, or harboring any other emotion about chemistry.com, you might investigate the history of www.whitehouse.com. Originally, an “adult” entertainment site, it was such an egregious perversion of Web addresses that somebody bought the domain name and converted it to a site about college financial aid.

 Maybe we should try to reclaim chemistry, too.

The simplest organic functionality of all is the humble methyl group. A single carbon and three hydrogen atoms seem relatively small and insignificant compared to most full-blown organic molecules.

You might even think that a methyl group here and there would hardly be noticed in the vastness of very large molecules like DNA. And if you did think this, you would be wrong.

Take the case of identical twins. They start life with exactly the same DNA, so it would seem to follow that their susceptibility to genetically based disease would be the same. If your twin had high blood pressure, got cancer, or suffered from lupus, you would, too.

In theory maybe this would be true, but in real life twins are often “discordant” in the traits they express. For example, when one twin has lupus—a disease in which the immune system attacks the body’s own cells—more often than not the other twin remains healthy.

A new study suggests the explanation may lie with the lowly methyl group, or more precisely the pattern of methylation of DNA. Reporting in Genome Research, Javierre et al. show that a healthy twin whose identical sibling has lupus has a decrease in DNA methylation in at least 49 different genes (letter published online 22 December 2009). Thus, while the inherited DNA base sequence may read the same, the methyl punctuation marks don’t, and this leads to alterations in gene expression.

This is a vital clue to a nasty disease. But alas, we don’t yet know what causes the methylation to vary, or what to do about it therapeutically. 

The study does point to the importance of non-inherited factors, probably environmental ones, that dictate outcomes. Once again the resolution of the nature vs. nurture debate falls squarely in both camps.

Last year I wrote about the prospects for an “invisibility cloak” that works by bending light around an object so it can’t be observed. (See my post of 29 January 2009.) Amazing as it seems, this is not only theoretically possible but has already been realized for a limited range of wavelengths.

New work from MIT imagines a “perfect invisibility cloak” that smoothly glides light of any wavelength around Harry Potter. Alas, these researchers also throw cold water on the theory that hides Harry’s cape. Their results show that shooting fast-moving charged particles at the invisibility cloak renders it visible via emitted radiation, even though light doesn’t detect the object (Physical Review Letters 103 [2009], 243901).

Come to think of it, cold water itself would detect the perfect invisibility cloak too. You might not be able to see it, but you could feel it, and it would repel water. Too bad, Harry, that invisibility doesn’t really make one undetectable.

When I was a graduate student in the 1970s, conventional wisdom held that light microscopy couldn’t resolve anything smaller than the wavelength of visible light (hundreds of nanometers). Electron microscopes overcame this size limitation but required “fixed” samples so no motions could be seen.

The dilemma this produces is that if you want to observe molecules, even relatively large ones like carbon nanotubes, you can’t also watch how they move in real time.

The stirrings of a solution to this problem come from the laboratory of Ahmed Zewail. Members of his Caltech research group conjured a new technique that essentially combines light and electron microscopy. Christened photon-induced near-field electron microscopy (PINEM), simultaneous impingement of femtosecond-long electron packets with intense optical pulses produces striking time-resolved images of carbon nanotubes and silver nanowires.

Although not applicable at this stage to aqueous biological systems like proteins and nucleic acids, PINEM is still an imaginative advance in molecular imaging, and it will be enormously useful to anyone interested in visualizing the world of nanostructures.