More concerns in bottled water, via Chemistry World

Everyone remember BPA? The stuff your water bottle now proudly proclaims it doesn’t have? There’s a new suspect in town to get flustered over. Bis(2-ethylhexyl) (2E)-but-2-enedioate.

Mugshot of the perp.

Mugshot of the perp.

But the Chemistry World link doesn’t answer a pretty fundamental question: Where’s this molecule coming from? Even the study’s authors skirt around the question a bit. I’d wager it’s a plasticizer: a small molecule added to the plastic in the water bottles to help make it more malleable and processable. The long branched hydrocarbon sidechains are a pretty strong hint. They prevent the plastic molecules (who love to hang out with each other) from getting too tightly packed and cozy, which would end up giving you a brittle inflexible water bottle. (The authors suggest it’s the decomposition product of some other molecule, but it sure looks like a conventional plasticizer to me.)

Because these types of molecules haven’t traditionally been regulated, or even monitored terribly closely, it’s tough to say if its concentration is too little to be much concerned about or not. That’s another reason that the study is nice – we’ve now got some definitive sleuthing that this molecule is in 18 different bottled waters from 13 different companies from varying countries (did I mention that’s how widespread it is, cuz that’s how widespread it is). It’s not possible to say with certainty how this molecule affects your health (Chem World notes that this particular one is not known to produce both the anti-androgenic and anti-estrogenic activities of suspected molecules), BUT it certainly ain’t gonna help your body any.

Original study (open access, woohoo!) here: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0072472

How’s it put together? Blow it up to find out!

Ok, this is just way cool. Researcher Martin Pitzer and a German-Swiss-Canadian team want to know how molecules are put together spatially, so in true mad scientist fashion, they’re blowing ’em up (Chemistry World writeup here). More specifically, they track bits of exploding molecule to figure out the stereochemical arrangement of the molecule’s atomic components – that is, where all the molecule’s pieces sit relative to each other pre-explosion.

Brace yourself, because their method also has a requisite badass name: Coulomb Explosion Imaging.

If you’ve studied organic chemistry, stereochemistry is probably familiar (if perhaps also the subject of recurring nightmares). It’s the study of how the various atoms of a molecule are arranged around each other. A non symmetric molecule can have identical atomic structure as its neighbor, even identical connections between atoms, but those atoms may be sticking out in front, while its neighbor’s are sticking out back. The arrangement is not simply rotational. Instead, the atoms are bound together differently. Images of two molecules cannot be superimposed over each other, no matter how you arrange them in space.

Blasting these with lasers is not recommended. (From unina.it, which coincidentally has a very accessible overview of stereochemistry.)

Far and away, everyone’s favorite metaphor for stereochemistry is your hands. Both the left and the right have five fingers: a thumb, a pinky, a few in the middle. Their constituent parts are identical. But there’s no way to superimpose one over the other in the same orientation. They’re mirror images of each other. In chemistry terms, they have opposite stereochemistry.

So who cares? Your body does actually. You may have heard of thalidomide. The story is quite famous and rather horrifying. Thalidomide was a drug prescribed to pregnant women to help fight morning sickness. Until it started causing genetic defects. Whoops. The idea is that one stereochemical arrangement of thalidomide was safe, but the other messed you up badly. Same molecule, if you count the atoms. But the relative position of those atoms made a drastic difference (the mechanism actually is assumed to be more complicated than that, where your body can turn one arrangement into the other, so really neither is “safe”).

So what’s new now? Well, not surprisingly, studying stereochemistry is a big deal, particularly for the medicinal community. The problem is that actually figuring out how a molecule is arranged ain’t easy. The most common method is to X-ray a very pure, pristine crystalline sample. But large complicated molecules and proteins are fiendishly difficult to make into perfect crystals. Here’s where the German-Swiss-Canadian team comes in: instead of trying to make the cleanest most perfect crystalline samples, they blow them up. By blasting samples with a laser, the molecules get stripped of their electrons. And in a strong electric field – BOOM! They blow apart, and the pieces hit a detector. Depending where each fragment lands, Pitzer and his colleagues can do some CSI work and trace the atoms back to their original molecular arrangement. Voila! X-ray-free stereochemistry!

Little known fact: Darth Vader was actually an unsung hero of stereochemistry.

A caveat here is how hard it is to track all those busted molecular fragments.  The trigger-happy researchers were only working with a small molecule made of five atoms.  Tracking all the possible fragments from just those five seems to be pushing the bounds of what their detector can do.  So this doesn’t immediately solve the problem of stereochemistry in large complex molecules, but it’s immensely cool and impressive.

Full, pay-walled Science article here: Direct Determination of Absolute Molecular Stereochemistry in Gas Phase by Coulomb Explosion Imaging

Element 115 get!

So we’ve a new element!  Good old 115.  So fresh, it’s still got its placeholder name: ununpentium.  The news has already been broken for a few days now, so here’s what some old-fashioned thinking on the topic has come up with.

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Just look at that majesty!

Odd facts related to #115

  • We’ll start easy: 115 of course refers to it’s place in the periodic table, not order of discovery.
  • It’s only maybe the 115th element we’ve discovered, chronologically.
  • It could maybe be the 116th, depending if you trust the as-yet unverified but previous discovery claim for #113 (yep, we officially verified #115 before #113).
  • Or maybe it’s the 117th (#117 on the table also has a prior claim in play).

Wait, what, we’re looking for ’em out of order?

Finding elements, not too dissimilar from time travel (diagram from Noah Ilinsky)

  • It’s not quite like Looper, Periodic Table Edition, but sort of.  Some elements are more stable and easier to make, so you find them first.  Also the IUPAC (the guys who confirm discoveries), are particular sticklers for replication by other labs, as they should be, so sometimes you’ve got to wait for backup.
  • The new #115 for example, actually had a claim made on it a decade ago before being replicated now (fun fact: that claim was by the #114 folks).
  • Researchers get really territorial about these claims, particularly if they feel they’re snubbed.  Go read the Wiki edits for #113.  Downton Abbey‘s got nothing on that drama.

What are we really gonna call it?

What could we do with it?

  • It only exists for fractions of a second before it decays. (I can’t immediately find how long it stayed #115 before decaying into other elements, but it’s probably not too different than the other elements around it.  So a few hundred milliseconds?)
  • We can hold antimatter – frickin’ antimatter for a hundred thousand times longer than we can hold #115 (current number I found is about 20 minutes).
  • So…I dunno?
  • Some kind of disappearing magic trick?
  • Side note: An non-exhaustive Wikipedia search (so take it how you will) seems to show Californium (element #98) as the highest synthetic element with a non-fundamental-research use.

“That’s decoy gold. You think I’d leave my gold in a locked safe buried underground where anyone could find it? You don’t know me at all.”

Next time you need a wingman for a Cash 4 Gold payout, I’m your guy. In the course of my day-to-day, I go through a lot of gold. We use it to make electrical contacts on test transistors. So I’ve got a pretty good handle on the gold market.

Common refrain from my office: “Wait, I just spent $700 on the same amount of gold two weeks ago? And now it costs $1100?!”

No pulling the wool over this guy’s eyes.

And when I say I go through a lot of gold daily, a lot = milligrams. Which comes to about 0.1% of the weight of a penny. A penny’s weight of pure gold, by the way, will run you $140.*

Gold (and other) plated pennies, from the always amusing ChemBark.

The funny thing about ordering gold FOR SCIENCE! is that it’s required to ship with a safety data sheet. I mean, gold is in one of those boxes on the periodic table, right? Well so’s arsenic! I demand you tell me what chemicals this gold is putting in my body (said nobody ever).

So here are my favorites from the gold safety data sheet:

“May cause eye irratation.” That’s right, don’t stick gold in your eye.

“First Aid Measures for skin: Wash with soap and water.” You don’t know where that gold’s been.

“Personal Protective Equipment: Wear safety glasses.” See above re: eye irritation dangers. Seriously dude, don’t stick it in your eye.

“There are no established workplace exposure limits for components of this product.” You can have your Scrooge McDuck gold-filled swimming pool, no sweat. Just don’t forget your safety goggles.

So there ya go, a nice chunk of The More You Know for the next time you’re bartering at the pawn shop. And don’t forget to bring me.

*At today’s rates anyway (July 30, 2013)**. So buy now!!

**Also important: the form of the gold. A penny’s weight in little 1/8″ inch pellets? $140. An actual penny-shape (scaled for weight of course)? $500.

How your perfume is like a discontinued Canadian drink

I’ve been brushing up on aerosols lately.  In the course of job hunting, I found an open position for an aerosol researcher at one of the DOE national labs (looking for: chemist, chemical engineer, or atmospheric scientist…take three guesses for what they’re working on).  My first instinctual answer to “What do I know about aerosols?” was a whole lot of nothing.  Spraypaint, right?  And PAM?  Somehow I doubt that’s enough for a successful application.

But the more I thought about it, the more I think I actually know, or at least could translate from parallel science, about aerosols.  I mean, they’re essentially a suspension of solid or liquid particles in a fluid right?  Here, of course, I’m using the broader-than-my-elementary-school-lessons and defining a gas as fluid (the 10 year old that still lives in me is shouting “Nuh-uh! Three phases: solid liquid and gas!”).

Because my brain has been in science writer mode lately, it started working through analogies.  How could I illustrate an aerosol?  Then it hit me – there’s already a not-so-terrible hands on macro-scale analogy for the micro-sized aerosols:

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ORBITZ!

If you’re old enough to remember Orbitz (and hopefully not cosmopolitan enough to have tasted it), you’ve seen a hands on model of an aerosol!  If you don’t remember, be thankful, and then take a look above.  There it is in all its glory!  A handful of small, squishy, sweet  particles dispersed through a fluid (which we can pretend is the fluid of air).  That right there is a simple proverbial ball-and-stick model of clouds, perfumes, spray paint, pollen, and volcanic ash.  Of course, the difference between a cloud, a dust storm, and Lady Gaga’s blood and semen perfume is all in the details.  There are some chemical details (how the particles or droplets interact with another and their environment, often through hydrogen bonds or van der waals forces), some physics details (gravity, the flow of the fluid/air around the particles), some geometric details (how closely those particles are packed together, how they’re shaped).  But for a simple model?  It’s all in one debatably tasty beverage.

Exciting baby-saving technology! Boring 3D printing.

By now you may or may not have heard how a 3D printed tracheal splint saved the life of an infant on the verge of having a collapse of the trachea. There are so many kinds of awesome in this story! (TIME writeup here; original paywalled writeup here.) 

The stent was custom designed and printed at the University of Michigan for the specific anatomy of the baby and served (as far as I can tell) as a sort of last ditch Hail Mary for fixing the problem. Digital designs of the trachea and splint were assembled, a biocompatible polymer was printed from those blueprints, and a life was saved.

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Image from Dr. Zopf and team’s report in the New England Journal of Medicine, linked above. Not just printing splints, but tracheas too!

For the baby (and for the rest of us who may need some custom-fit medical TLC), this is an amazing use of 3D printing. It’s a perfect example of why every medical institute and hospital should have a 3D printer. But as a posterchild for the technological potential of 3D printing?  I can’t help but feel it’s kind of lame.

See, the stent was printed from a single semi-rigid material – polycaprolactone. Yawn, been there. Printing a single polymer ain’t that impressive anymore. Hell, folks have been doing this since before the marketers ever started calling it 3D printing (just one example: http://www.sciencedirect.com/science/article/pii/S0378517397001658). 

Popular internet disclaimer here: I am not a doctor. But here’s what I imagine the priorities are for a splint:

  1. Mechanical stability (“Hey splint, hold my trachea open please? Got it? Not gonna drop it on your toe in a few seconds? Great!”)
  2. Bio-compatibility (Cells aren’t exactly the sharpest cards in the deck. They may not realize that crazy thing which was just jammed in your neck is actually saving your life instead of, say, being any other number of things that are not so beneficial when jammed in a neck which require immediate removal please.)
  3. Degradability (Remember as a kid outgrowing your favorite t-shirt but trying to squeeze into it anyway, often with dramatic seam-rippage? Now imagine a stent squeezing down on your trachea like that after it grows. No thanks.)

We’ve been doing stents and splints for a long time. We’ve figured out how to hit those priorities quite well. The real exciting news here is time and customizability. The fact that the doctors have access to a 3D printer which could print a stent exactly matching the infant’s anatomy faster than they could get one traditionally made is awesome! Tech with a low barrier to entry (cost, complexity, etc.) having a significant societal impact is always a good thing.

But just printing a biodegradable plastic splint is not terribly impressive. There’s not a whole lot technologically interesting here. More often than not, the rallying cry I hear around 3D printing centers around printing any object you could conceivably want. And that’s simply not achievable now. What makes something a table or a sponge or a computer isn’t just a shape (I would be remiss not to mention cargo cults). It’s the materials used to make them. 3D printing has great control over shape. It has terrible control over materials.

Cago cult plane

“Pilot to tower: I feel like I’m flying a bundle of wood up here!”

Maybe this is just the jealous materials scientist in me talking.  “Guys, there are all these crazy wild materials and composites you could start printing!  Pretty pretty please?” Making, say, a squishy stretchable biocompatible doodad with integrated electronic components is really hard from a conventional manufacturing standpoint. It requires at least three different classes of materials needing to be combined and assembled in intricate ways with high spatial fidelity. We’ve got all of these materials, and we know they can be 3D printed. So why are we still stuck with simple rigid mechanical scaffolds and hobbyist parts? The hard science is done. All (ok, maybe most) of the details you could likely want about the print-ability are already out in the scientific literature right now. Further studies on the fundamental science are going to be few and far between. “It’s an engineering issue,” I can hear the NSF respond to your 3D printing grant proposal as they decline funding.

I’ve read a lot and interviewed with some 3D printing companies, often in job hunting mode (yes 3D printing dudes and dudettes, I’ve asked some of you for jobs). None of them seem to be thinking about materials in any meaningful way, as far as they’re willing to talk about. Which is a shame, because the platform is itching for it. “Yeah, we want to make squishy things and electronic things and biological things!” they say. But then you ask how, and they get fuzzy on the specifics. And by fuzzy, I mean THERE ARE NO MATERIAL SCIENTISTS ON YOUR TEAM WITH THE LEEWAY TO DO ANYTHING INTERESTING. There are one or two exceptions. Stratasys, for example, seems like they’ve got their heads on right for the long term. The other guys? Unless they really start thinking about composites, and multi-material printing, and moving away from ABS, there’s going to be a long slide into stagnation and exclusive appearances on Etsy jewelry sites.

Make it so, Number One!

Captain Picard would probably replicate a whole lot less Earl Grey if it came out as a cup full of plastic.

 

Anyway, all of the above is small potatoes: a bit of nitpicking and cynicism about the reporting around 3D printing I’ve seen. Because I absolutely do not want to overshadow the real fantastic headline here: Science – Now saving babies faster and better! If the worst 3D printing can do is save lives, I think we’re in pretty great shape.

‘Science cafes’ feed hunger for technical understanding

Shameless self-promotion time!  It’s my first freelance piece, talking about local science cafes.  Print newspapers are the way of the future, right?

What I do find kind of interesting is all my science friends who I’ve linked this to.  There’s been a lot of surprised excitement when they find out that there are, in fact, science cafes near them.  There’s probably one near you too.