Stories tagged chemistry

Feb
25
2013

OMG! Can nothing stop them?: According to a new study, mosquitoes, those buzzing, biting, itch-producing flying pests that make life miserable for many of Earth's inhabitants (mainly we humans), can easily adapt to Deet, one of the commonly used ingredients in insect repellents.
OMG! Can nothing stop them?: According to a new study, mosquitoes, those buzzing, biting, itch-producing flying pests that make life miserable for many of Earth's inhabitants (mainly we humans), can easily adapt to Deet, one of the commonly used ingredients in insect repellents.Courtesy Mark Ryan (with photo help from NASA)

We've all seen them, those great B-films where a giant, vicious monster from under the sea, or invaders from outer space arrive to cause mayhem across our cities and generally mess up our way of life. In the end, it seems no matter who or what it was that was attacking us, be it Mothra, Godzilla, or some race of belligerent extra-terrestrials, we could always count on the military to save our collective behind.

Unfortunately, with mosquitoes, that might now be the case anymore.

Scientists are reporting that Deet, one of the most widely used active ingredients in insect repellents, loses its effectiveness against mosquitoes shortly after those ubiquitous, blood-seeking winged vermin are first exposed to it.

Deet - the common name for N,N-diethyl-meta-toluamide - was developed by the US Army after the Second World War to help combat insects during jungle warfare. It was used extensively in the Korean and Vietnam wars, but mosquitoes seem to be able to adapt quickly to it.

"Mosquitoes are very good at evolving very very quickly", said Dr. James Logan of the London School of Hygiene and Tropical Medicine and co-author of the study. "There is something about being exposed to the chemical that first time that changes their olfactory system - changes their sense of smell - and their ability to smell Deet, which makes it less effective."

So what I want to know is where does that leave us here in Minnesota where the mosquito constantly competes with the Common Loon for the title of State Bird? Maybe it's time to start digging the bunker in the backyard.

SOURCE and LINKS
BBC Science news
Original study at Plos One
The Life Cycle of the Mosquito
All about mosquitoes on NatGeo

Saw this rerun of WKRP in Cincinnati last night. This clip really puts the "informal" in informal science education. I believe this episode dates back to like 1981, but the jargon is still up-to-date.

"Apparently melted" sugar
"Apparently melted" sugarCourtesy Delphine Ménard

Just because everyone knows it's true, doesn't make it so. For centuries, candy makers have wrung their hands over the vagaries of sugar. See, sugar doesn't always melt at the same temperature. Turns out, that's because it's not really melting. It's decomposing.

Check out the article
for more information.

"We saw different results depending on how quickly we heated the sucrose. That led us to believe that molecules were beginning to break down as part of a kinetic process," said Shelly J. Schmidt, a University of Illinois professor of food chemistry.

Schmidt said a true or thermodynamic melting material, which melts at a consistent, repeatable temperature, retains its chemical identity when transitioning from the solid to the liquid state. She and Lee used high-performance liquid chromatography to see if sucrose was sucrose both before and after "melting." It wasn't.

"As soon as we detected melting, decomposition components of sucrose started showing up," she said.

To distinguish "melting" caused by decomposition from thermodynamic melting, the researchers have coined a new name—"apparent melting." Schmidt and her colleagues have shown that glucose and fructose are also apparent melting materials."

Feb
10
2011

Chop it off and send it in!
Chop it off and send it in!Courtesy miss pupik
A couple weeks ago I posted a link to a project in which Dr. Patrick Wheatley was soliciting donations of hair for geochemical research. Intrigued, I contacted Patrick to ask him more about the hair project.

Me: What do you look for as you test the hair?

Patrick: I'm looking for changes in the ratios of isotopes in various elements. I hope to tie the changes in isotopic ratios to differences in geography, either through differences in the isotope ratios of local water supplies or fundamental deferences in the geology of the region where the hair was grown.

Me: How do those isotopes get in our hair in the first place?

Patrick: They are incorporated through our drinking water or diet.

Me: What will your findings help scientists do or understand? Is there a practical application for this research?

Patrick: This research is driven by a possible forensic application, knowing the past whereabouts of victims of crimes (perhaps dead and unable to talk about where they were or perhaps held in a secret location) or suspects of crimes (maybe unwilling to talk about where they have spent time recently). There are also possible medical applications.

You can still send hair in for the project. More information can be found at the project's website.

Patrick Wheatley, a geochemist with Lawrence Berkeley National Laboratory, is collecting hair for a research project. You can help by mailing him some. Intrigued? Read more here.

You know what's cool? Animation. And folks with the same skills used to bring you Red Dead Redemption and Toy Story 3 are also hard at work creating scientific visualizations that show the machinery of life.
Aug
31
2010

This kid is sitting on a fortune!: That balloon will put him through college, assuming he doesn't blow it all first on candy and blackjack.
This kid is sitting on a fortune!: That balloon will put him through college, assuming he doesn't blow it all first on candy and blackjack.Courtesy Lars Plougmann
Y’all ever see Mad Max? Or Mad Max 2: The Road Warrior? Or even Mad Max 3: Beyond Thunderdome?

Some of you surely have, and I salute you. For the rest of you, the short description is this: a handsome young Australian actor, who we should just assume is now dead, played a lone wanderer, drifting across a post-apocalyptic wasteland. During the course of his adventures, he meets Tina turner, a really weird looking pilot (twice?!), a grunting, boomerang-throwing feral child, a man named Toe-cutter, and an awesome giant/little person team (sort of like Jordan and Pippen, but more inclined towards stranglings). It’s all very exciting! But the most important part of the Mad Max trilogy is this: he lives in a world without gas. Everybody was so busy blowing each other up that they forgot to be careful with their oil, so by the time Max rolls around, people are freaking out trying to get a few more drops of “the precious juice” for their dune buggies and flame throwers.

And so we come to our news item, and this afternoon’s future-dread focus: helium. If you look at the Mad Max summary and pretend “gas” refers to helium gas instead of gasoline, and if you replace “dune buggies” with “scanning equipment,” and “flame throwers” with “party balloons,” it’s a pretty decent analogy.

See, we’re running out of helium. And when it’s gone, it’s gone forever.

The above statement brings to mind two points (at least for me):
1) No we aren’t. Shut up.; and
2) Even if we are running out of helium, who cares? I can fill up my party balloons with air, or Cheesewhiz, or something.

If you read the article linked to above (or one of the many articles on the subject that came out last week), you’ll find that the answer to point 1 is, yeah, we kinda are, and the answer to point 2 is, it’ll be sad to see floating party balloons go, but they’re the least of our problems. It’s all dune buggies and flame throwers from here on out.

The problem is that helium is non-renewable. We talk about oil being non-renewable, but helium is even more non-renewable. See, helium only comes from fusion reactions (hydrogen atoms slamming together to form heavier helium), or from radioactive decay (heavier elements breaking apart at the atomic level to form lighter helium). Hydrogen fusion only happens in stars (scientists are trying to replicate it as an awesome source of nuclear energy, but don’t hold your breath), so all of the helium on our planet comes from underground, where gases from radioactive decay have become trapped.

We’ve got a nice big planet here, and we’ve got lots of helium, but we’ve just been farting it away, and once helium is released into the atmosphere, it’s gone to us for good. And we’re currently farting away helium at such a tremendous rate that the gas could be all but unavailable within a couple generations. The reason for this is that it’s actually official policy to fart away helium. (More or less.)

A huge portion of the world’s helium has been mined from the American Southwest, and for a long time we were actually pretty good at storing it—we pumped it back underground into a huge system of old mines, pipes and vats near Amarillo, Texas, in a facility called the US National Helium Reserve. We stored the helium because it was strategically useful to the country—it was vital for rocket operation during the Cold War. But in 1996, a law was passed requiring the helium to be sold off, all of it, and by 2015. I’m not totally clear on the reason for the law. I suppose the idea was that the Cold War was over, and by selling the helium, the US National Helium Reserve could be paid for (sort of a Gift of the Magi kinda thing, but whatever.) Congress, however, decided that the price of the sold helium would remain the same until it was all gone, so even as available helium became scarce, it would never be more expensive.

This broke the law of supply and demand, and having this vast, vast supply of helium go on sale for cheap meant that all the helium in the world had to be cheap too. Helium has become so cheap, in fact, that there’s no economic incentive for recycling it—recapturing it after use is so much more expensive than just buying new helium, people have just been letting the used helium drift away, where we’ll never be able to reclaim it. Normally, when a resource becomes more scarce, its price will go up, and people will be better about using it. (For an example, see gas prices and fuel efficiency in cars.) Not so with helium, thanks to that 1996 law. And pretty soon, say some scientists, we’ll be running out of the precious gas.

The “precious” part is there because helium is useful for a lot more than party balloons. (Although they’re ok too.) The properties of helium make it an excellent coolant for medical scanning equipment, and the sort of detectors used in super colliders. It’s also used in telescopes, diving equipment, rockets (NASA is a huge user—and waster—of helium), fusion research, and airships. (And don’t laugh about that last one—as the price of fuel goes up, the prospect of eventually moving cargo with lighter-than-air aircraft, like blimps and zeppelins, is becoming more likely. And hydrogen is a little bit too explodey to be a great alternative lifting gas.)

Helium is so desired, and is being wasted at such a rapid rate, claims Robert Richardson (a Nobel Prize-winning physicist, whose research was on helium), that a single helium-filled party balloon ought to cost about $100.

That’s right: $100. It’s that, or we keep going until there’s no helium left. And then... it’s Thunderdome. You know the rules—there are none.

This article describes a new sugar-based compound in development by researchers at the City College of New York that has the potential to make oil slick cleanup a lot easier in the future. The compound turns the oil to gel, which can be easily skimmed from the water's surface. This is a great alternative to dispersants like the ones BP used because it's nontoxic and shouldn't harm ocean organisms. Check out the video on the same page of that stuff in action--pretty cool!

And when I've got a headache, I reach for aspirin and caffeine, sometimes with a little hit of acetaminophen besides. Today, when I popped open the aspirin packet, I got wondering about that faint vinegar-y smell that aspirin often has.

Magic stuff: even if it's kind of smelly.
Magic stuff: even if it's kind of smelly.Courtesy jypsygen

Turns out that's chemistry in action. And probably also lousy storage. (And, yes, I realize Yahoo! Answers is not a good source, but some additional poking around confirms that this is the correct explanation, and the best written one, too.)

Jun
25
2010

Did you know that making bricks emits more carbon each year than air travel? It turns out that for each brick made in a kiln, 1.3 pounds of carbon dioxide are spewed into the atmosphere. With 1.23 trillion bricks made annually, those emissions add up.

Luckily, there's an architect-cum-chemist who has discovered how to make bricks out of sand, microbes, and urine. Ginger Krieg Dosier, an assistant architecture professor in the United Arab Emirates, had apparently been experimenting with growing bricks for years before she finally happened on the right combination. She still has some issues to work out in the design, but her technique could produce bricks as hard as marble!

According to Metropolis, which gave Ms. Dosier a Next Generation Design award for her work, "If Dosier's biomanufactured masonry replaced each new brick on the planet, it would reduce carbon-dioxide emissions by at least 800 million tons a year."