Field of Science

Oprah's take on quantum mechanics - and mine

I was checking my blog stats (read seriously procrastinating folding the laundry) and noticed that one of the search terms that was sending surfers to my other blog was "Oprah's take on quantum mechanics". She has one?

I promptly popped it into Google to see what would come up. I had to know.

I found out. The Law of Attraction. Think and you can change what happens. Proven by quantum mechanics. The Quantum Cleanse. (Don't ask - you don't want to know.)

Somehow the word "quantum" manages to sound simultaneously mysterious and scientific, and so people attach it to things that they want to sound simultaneously mysterious and scientific. Like diets and the power of positive thinking, or even theology.

I named my personal blog "Quantum Theology" as a play on the two fields I'm trained in: quantum mechanics and theology. Recently a friend of almost forty years wondered just exactly what was quantum mechanics - just what do I do for a living? Repair broken quantums?

When I say something is quantized, I don't mean it's mysterious, I mean that only certain values are allowed, and nothing in between. A good everyday example is your shoe size. You are a 5 or a 5 1/2, but never a 5 1/6. Off the rack shoes (are there any other kind these days?) are quantized.

To a physicist or physical chemist, a quantum is a fixed portion of energy. (The word was coined by Max Planck in 1900.) Quantum mechanics considers the interaction of energy and matter on the atomic level. What happens when light hits an atom? Why is it that only certain amounts of energy can be absorbed? How is it that matter can behave as a particle, and as a wave? Evidence that matter could behave like a wave suggested to Erwin Schrodinger that he could write an equation to find a mathematical description of this behavior.

So what is it I actually do? I use quantum mechanics — specifically solving Schrodinger's handy little equation — to predict the structures of molecules and their energy, then use that information to think about what molecules might exist, or how hard it would be for them to react and what products are likely to form. Right now I'm exploring molecules that are uncomfortably twisted - and topologically "interesting" (Moebius strip molecules).

My name is Bond.....

Ionic Bond. Taken, not shared.

I caught this pun on a t-shirt at an ACS meeting a few years back. In that same vein In the Pipeline is highlighting this paper in ChemBioChem: Live-Cell Imaging of Cellular Proteins by a Strain-Promoted Azide–Alkyne Cycloaddition. Don't see the connection? Check out the abstract:

Live and let dye: Three coumarin-cyclooctyne conjugates have been used to label proteins tagged with azidohomoalanine in Rat-1 fibroblasts. All three fluorophores labeled intracellular proteins with fluorescence enhancements ranging from eight- to 20-fold. These conjugates are powerful tools for visualizing biomolecule dynamics in living cells.

The NY Times blog on applying to college mused today about the perils of being overly cute on college applications, I wonder what advice they'd give to journals on this score?

Elemental Audio Visual

A chemistry friend shared this cover of Lehrer's classic litany of the elements:

It's worth the 85 seconds it takes to watch! The subtext is fascinating....when the elements flash by you can see the alternate searches Google is proposing. The searches for oxygen bars, I get, but how many people really need to know the price of lutetium? ($5.89 per gram for 99.9% pure lutetium metal here, or $13.99 per gram for "used" on eBay — your choice, act fast if you want to bid, though).


H/T to Dr. Lisa!

Urban Myths of Chemistry Redux: The Enantiomers of Thalidomide

A few months ago I mused about the persistence of an urban myth of chemistry - the meaning of the p in pH. The musings grew into an essay which appeared in Nature Chemistry in August. [Urban legends of chemistry, Nature Chemistry 2, 600 (2010) - caveat, you or your institution need to have a subscription]. The in vivo behavior of the enantiomers of thalidomide turns out to be grist for another persistent myth.
"Ryoji Noyori, who shared the 2001 Nobel Prize in Chemistry for his contributions to asymmetric synthesis, uses the tragedy of thalidomide to open his Nobel lecture: 'A compelling example of the relationship between pharmacological activity and molecular chirality was provided by the tragic administration of thalidomide to pregnant women in the 1960s. (R)-Thalidomide has desirable sedative properties, while its S enantiomer is teratogenic and induces fetal malformations. Such problems arising from inappropriate molecular recognition should be avoided at all costs.'

A close reading of these tales raises more than a few flags. Details differ — was thalidomide marketed for depression or insomnia or morning sickness or to prevent miscarriage? (No, yes, yes and no.) Here is another urban legend of chemistry — with multiple authoritative sources, varying in detail, superficially reasonable, persistent — and with an incredibly compelling plot line. Yet it's not true — as even the tellers acknowledge on occasion. Both forms are teratogenic when administered, as they rapidly racemize in vivo.

Why would chemists pass on urban legends (and ones known to be false, at least in part)? Carl Jung suggested that 'no intellectual formulation comes near the richness and expressiveness of mythical imagery'" ....[read the rest at Nature Chemistry]

Prof. Israel Agranat (whose paper about chiral switches I reference in the essay) wrote me to share that it's not only chemistry textbooks in which these myths circulate. He pointed me to examples, including this one, from the law literature:

Citalopram is a racemate... Such molecules are called chiral (from χειρ, a hand) because, like a pair of hands, they are mirror images which cannot be completely superimposed on each other. They are conventionally designated (+) and (-). It has been well known for many years that, despite their similarities, the two enantiomers may bind to different proteins and produce different biological effects. The most notorious example was thalidomide, which consisted of a (+) enantiomer which was effective to prevent morning sickness in pregnant women and, unknown to the consumers, a (-) enantiomer which was teratogenic and caused severe birth defects." — excerpted from Lord Hoffman's decision of the England and Wales Court of Appeal in the Escitalopram oxalate (Cipralex, Lexapro in the US) patent litigation, H. Ludbeck A/s vesus Generics (UK)
So why do we pass on the legends? My short answer is that resistance is futile!