A study by Noah Fierer and co-workers at the University of Colorado at Boulder suggests that the mix of bacterial flora each of us leaves behind on, say, our computer keyboard or mouse, may be sufficiently unique to identify us:

"Each one of us leaves a unique trail of bugs behind as we travel through our daily lives," said Fierer, an assistant professor in CU-Boulder's ecology and evolutionary biology department. "While this project is still in it's preliminary stages, we think the technique could eventually become a valuable new item in the toolbox of forensic scientists."

The study was published March 15 in the Proceedings of the National Academy of Sciences. Co-authors on the PNAS study included Christian Lauber and Nick Zhou of CU-Boulder's Cooperative Institute for Research in Environmental Sciences, or CIRES, Daniel McDonald of CU-Boulder's department of chemistry and biochemistry, Stanford University Postdoctoral Researcher Elizabeth Costello and CU-Boulder chemistry and biochemistry Assistant Professor Rob Knight.

Using powerful gene-sequencing techniques, the team swabbed bacterial DNA from individual keys on three personal computers and matched them up to bacteria on the fingertips of keyboard owners, comparing the results to swabs taken from other keyboards never touched by the subjects. The bacterial DNA from the keys matched much more closely to bacteria of keyboard owners than to bacterial samples taken from random fingertips and from other keyboards, Fierer said.

Here's the abstract for Fierer's paper at PNAS.

Two galvanized nails set in a plug of plaster-of-Paris. That's it. The Cheap Vegetable Gardener, who created the sensor for an automated grow box project, explains:

Technically a gypsum block measures soil water tension. When the gypsum block is dry it is not possible for electricity to pass between the probes, essentially making the probe an insulator with infinite resistance. As water is added to the problem more electrons can pass between the probes effectively reducing the amount of resistance between the problem to the point when it is fully saturated where the probe has virtually zero resistance. By using this range of values you can determine the amount of water than exists in your soil.

[via Hack a Day]

Xylocopa Design (of Build-Your-Own Ratmobile fame) just added this beautiful Mysterious Mushroom Puzzle to their Makers Market store:

These gorgeous engraved wooden mushrooms fit together to make a 6" square - but in only one configuration! Assembling them may not look so bad, but trust us, it's no simple task. Each mushroom is based on a different, real species of fungus. Fun and frustration for adults and children alike. The mushrooms are crafted from assorted hardwoods - maple, cherry, walnut, mahogany, padauk, and bloodwood - and finished with an all-natural Tung Oil finish. The storage tray is made of birch and comes with an engraved cheat guide.

Lately we've had lots of folks writing in seeking practical advice on collecting tissue samples for use in studying whaleborne disease. I had no idea there were so many amateur cetopathologists out there!

Anyway, as you folks know--all too well, I'm sure--it is extremely difficult to collect blood from a wild whale without injuring or killing it in the process. However, and as even a child can tell you, the next best thing to live whale blood is live whale snot. Turns out it spews from their blowholes when they exhale, so the process is really very simple:

1. Find whale.
2. Hold petri dish over blowhole to intercept spout.
3. Return to lab, enjoy sample.

Step 2 is actually the hard part. And although your first instinct may be to just jump in your rowboat, paddle out to a whale pod, lean way out over the side with your sample container, and wait, that's actually not as safe as it might sound. Each year, untold millions of scientists die attempting this maneuver. Their sun-bleached bones litter beaches all along the Pacific coast.

Enter Dr. Karina Acevedo-Whitehouse, of the Zoological Society of London. Her recent paper in Animal Conservation (abstract), irresistibly entitled "A novel non-invasive tool for disease surveillance of free-ranging whales and its relevance to conservation programs," introduces the ground-breaking methodology of strapping a petri dish to a toy RC helicopter and flying it into the spout. This landmark work stands not only to revolutionize our understanding of whale disease, but to save countless lives, and establishes Dr. Acevedo-Whitehouse as a serious contender for this year's (Ig) Nobel Prize.

[via The Thoughtful Animal]

P.S. Dr. Acevedo-Whitehouse, you are made of awesome. And although I have never met you and probably never will, I love you with all my heart.

We have blogged about American assemblage artist Ron Pippin's work before, with a focus on his wunderkammer pieces. But he's been busy since then. Fair warning: Much of Pippin's work uses real animal parts, and although I personally find it very beautiful, some viewers may be disturbed and/or offended. [via The Automata / Automaton Blog]

This week's clever maker-entrepreneur award goes to Etsy sellers Cleaner Science, who make and sell these awesome soaps that look like petri dishes full of growing germs. They're easy to make (I presume), inexpensive to buy, light enough to ship cheaply, and totally original. Home run! Bonus: some include glow-in-the-dark spots! [via Geekologie]

These fantastic infographics are from designer Stephen Taubman. In the first, he illustrates how all three factions would fare in the forthcoming ultimate three-way cage match for evolutionary dominance between aliens, predators, and human beings. Especially helpful is his advice, under "If you meet a Predator," not to attempt to engage it with a flying side-kick. This was the mistake that I made.

The second graphic explains the physics behind what Boing-Boinger Jimmy Guterman has described as "the greatest scene ever in the greatest movie of all time," viz. the destruction of a cruising jetliner by the eponymous "Mega Shark" from Mega Shark vs. Giant Octopus. You may be interested to know, for instance, that Mega Shark's air attack requires breaking the surface of the water with a velocity of 710 km/hr, which is faster than a bullet train but not quite so fast as a Tomahawk missile.

Now available worldwide as an iPhone app in iTunes [iTunes link], Project Noah aims to become a common mobile platform for documenting the world's organisms. Beyond documentation, the iPhone app offers users an opportunity to participate in ongoing citizen science research projects through specifically designed field missions and can be used as a location-based field guide as well. All contributors are connected with an online community, bridging the documentation process.

The project has been picking up steam lately and has been featured by the Council for the Internet of Things, IBM's Smarter Planet, GOOD and is in pilot studies with schools for use as an educational tool.

Another very cool and innovative technology is the iWalk PowerFoot One.

This bionic foot-ankle prosthesis was pioneered by a researcher at MIT, Dr. Hugh Herr. I had the pleasure of meeting him last year and was truly inspired by the encounter. He epitomizes passion for engineering, and is one of the few engineering researchers I've met who deftly and simultaneously applies scientific research and engineering technology to his work. A documentary was made about Dr. Herr, and the trailer is definitely worth a moment to view.

THE great hope of transplant surgeons is that they will, one day, be able to order replacement body parts on demand. At the moment, a patient may wait months, sometimes years, for an organ from a suitable donor. During that time his condition may worsen. He may even die. The ability to make organs as they are needed would not only relieve suffering but also save lives. And that possibility may be closer with the arrival of the first commercial 3D bio-printer for manufacturing human tissue and organs.

The new machine, which costs around $200,000, has been developed by Organovo, a company in San Diego that specialises in regenerative medicine, and Invetech, an engineering and automation firm in Melbourne, Australia. One of Organovo’s founders, Gabor Forgacs of the University of Missouri, developed the prototype on which the new 3D bio-printer is based. The first production models will soon be delivered to research groups which, like Dr Forgacs’s, are studying ways to produce tissue and organs for repair and replacement. At present much of this work is done by hand or by adapting existing instruments and devices.

Photos by Tom Little.

Michelle Stitzlein makes these beautiful giant butterfly sculptures entirely from junk, "including piano keys, broken china, license plates, rusty tin cans, electrical wire, bottlecaps, and other miscellaneous items." [via Dude Craft]

From the pages of MAKE:

Bruce Stewart covered Michelle Stitzlein's butterfly sculptures in MAKE 19.

"Microfluidics" (Wikipedia) is kind of a blanket term that covers manipulation of liquids on a very small scale. An inkjet printer head is an everyday example of a microfluidic system, but many of the more exciting applications are in biochemistry and/or medical diagnostics, where mass-produced "lab-on-a-chip" systems incorporating complex networks of tiny fluid channels could one day bring complex analytical procedures, that once were practical only in the laboratory, out into the field. Many of the same technologies that are used in the production of semiconductors can be applied to the manufacture of microfluidic systems.

As in semiconductors, however, the costs of prototyping labs-on-chips can be quite high. Many of you may recall the buzz surrounding UC-Irvine professor Michelle Khine's recent discovery that inkjet-printable shrinky-dink plastic could be used to rapidly prototype microfluidic systems.

This excellent video features Stanford's Derrick Davis and Tom McFadden rapping about glycolysis and pyruvates. [via Tierneylab]

Before you protest, as I initially did, that some things are so simple and fundamental that they don't really need high-tech "improvements," realize that this device is being developed for and targeted at medical professionals, who, per this New York Times article covering the developing technology, "often have to wash their hands dozens of times a day -- and may need a minute or more to do the process right, by scrubbing with soap and water."

Room temperature plasma is reportedly very effective at sterilizing surfaces, and is already in use to clean inanimate surfaces and instruments. The plasma is produced by ionizing ordinary air, so no separate gas supply is needed. Apparently the central design challenge is making sure the box --which is basically just a high-voltage power supply--is safe to stick your hand into, and remains that way over the lifetime of the device. The plasma itself supposedly causes no discomfort and is safe for the skin, although you'd think, if they really believe that, somebody would've provided a photo showing a bare hand in contact with it, rather than one so conspicuously gloved.

You may have heard of this guy. Born on this date in 1809 in Shrewsbury, Shropshire, Charles Robert Darwin (Wikipedia) would go on, in 1859, to publish On The Origin of Species, a book which is surely among the most influential ever written. In it, Darwin first proposes the idea that all of life descends from common ancestors, and that its diversity can be explained by a process of evolution driven by natural selection. He died in 1882, aged 73, and was afforded the exceedingly rare honor, especially for a scientist, of interment in Westminster Abbey.

Image courtesy Jonathan Fiamor Photography.

When I was at UT Austin, a school which is famously car-unfriendly, it was rumored that one of the elder patriarchs of the College of Natural Sciences--a man who had multiple doctoral degrees and had been given countless awards for his work both as a scientific researcher and an educational administrator--had once quipped that the honor that was most valuable to him, on a daily basis, was the "O" parking permit that let him leave his car literally in the shadow of UT's iconic tower.

Well, in terms of available parking, UC Berkeley makes UT Austin look like an airport remote lot in Iowa on a Wednesday in the dead of winter. And according to this official page there are presently seven living Nobel laureates on the faculty there, so I'm guessing there must be at least seven of the prestigious NL parking spaces. Supposedly, regular mortals have to shell out $50 for presumptuous malparkage among the elite.

Photo courtesy Flickr user Scoutj.

This article just drew my attention to the interesting story behind carmine, which is a pigment precipitated from carminic acid (shown below) extracted from the bodies of Dactylopius coccus, the so-called "cochineal" insect, of which the acid comprises up to 24% of dry body weight. The cochineal is a parasite of cacti of the genus opuntia, from which it has been harvested in South America since pre-Columbian times. It is carmine that produced the "red" of the famous British "red coats," and today carmine is still produced in great quantity for use in fabric, cosmetics, and as a natural food coloring. (Vegans beware!) [via Neatorama]

British sculptor Tessa Farmer makes these amazing little vignettes featuring 1-cm-tall skeletal fairies made from "bits of organic material, such as roots, leaves, and dead insects" pitted against actual insects and other, larger taxidermied critters. Both creepy and awesome. Crawsome? [via Dude Craft]

If you're interested in doing gel electrophoresis (e.g. for DNA fingerprinting) at home, there are certainly easier ways to get a gel casting kit, but I wanted to throw some more props at Thingiverse user cathalgarvey, who recently also brought us a printable microlathe and a printable centrifuge attachment for a motor tool. He's fast making a name for himself as a forerunner in the design of practical printables. Might I suggest a printable microtome next?

From the pages of MAKE:


MAKE Volume 7, page 66 - Backyard Biology

This dude is Hans Christian Ørsted, whose 1820 discovery that electric current produced magnetic fields was, supposedly, entirely accidental: He was preparing a voltaic pile for a lecture demonstration and there happened to be a compass lying nearby. He has become a sort of mascot for the Journal of Serendipitous and Unexpected Results (JSUR), a new open-access journal initiative that hopes to provide a forum for life and computer scientists to publish results they lucked into and maybe can't fully explain. From their website:

Can you demonstrate that:

* Technique X fails on problem Y.
* Hypothesis X can't be proven using method Y.
* Protocol X performs poorly for task Y.
* Method X has unexpected fundamental limitations.
* While investigating X, you discovered Y.
* Model X can't capture the behavior of phenomenon Y.
* Failure X is explained by Y.
* Assumption X doesn't hold in domain Y.
* Event X shouldn't happen, but it does.

JSUR is now accepting manuscripts for their first issue. [via Boing also Boing]

I love this bird-feeder tutorial from Instructables user me13lake. It's not flashy (indeed, with a title like "Small simple horizontally mounted squirrel resistant/proof bird feeder that requires no specialist tools to make," I'm guessing it was written by a scientist or engineer) but it's well thought-out, easy and inexpensive to make, and it looks like it would work very well. The clear squirrel-guard rotates freely so they can't get a grip, and can be made from a 2-liter plastic bottle. Or you could try cutting one from a glass bottle.

Dr. James Carter is a professor in the Department of Geography-Geology at the University of Illinois. One of his many interesting pages collects photos and other reports (dating back to 1884) of so-called "hair ice," "haareis," or (my fav) "silk frost." The fibrous ice crystals seem to be caused by the pore structure of certain woods, and only forms where the bark has been removed. Reportedly, the phenomenon is reproducible: if you find a piece of wood growing hair ice, you can warm it up, then re-freeze it, and it will grow hair ice again. [via Neatorama]

With our Make: Science Room in full swing, I'm reminded of the Backyard Biology issue of MAKE. In Volume 07, we have articles that include freezing and reviving a garden snail, how to set up a home mycology lab, plant grafting and pollination, how to replicate your own DNA, and the cornerstone piece, Dr. Shawn Carlson's article on how to extract, purify, and experiment with DNA. Unfortunately, you can no longer get back issues of Volume 07 or the Next Year box set that it's a part of, but here's Dr. Shawn's article in full to get your biology wheels turning. Also, if you're a subscriber, you get full access to all 20 back issues of MAKE through our Digital Edition. And be sure to step into the Make: Science Room for tons more projects, tools, and techniques for backyard scientists.

Kitchen Counter DNA Lab
By Dr. Shawn

DNA is perhaps the most extraordinary structure in all creation. Its famous double helix is the longest molecule known and regulates the life processes in every cell on Earth. Even more, the code that DNA carries is the actual blueprint of life itself. The human recipe, for example, consists of roughly 3 billion molecular bits of information laid out in a precise sequence. Perhaps most amazingly, this miraculous winding staircase directly links every creature on Earth to our ancient and common past — far back to when evolution first began shaping the biological forms that would ultimately populate the world we know today. By examining the differences between the DNA in our bodies and that in other organisms, we can tell when our species diverged from chimps, apes, and even primordial fish.

The properties of this massive molecule are so mysterious and wondrous that most folks assume only the enlightened priesthood of laboratory biologists can extract and study it. Not so. In fact, anyone can extract, purify, and experiment with DNA at home.

When released from a cell, DNA typically breaks up into filaments. In solution, these strands have a slight negative electric charge, which makes for some very useful chemistry. For example, the more negative sections of one DNA strand will tend to attract the more positive regions of another. This causes DNA molecules to clump together and fall out of solution. However, if salt is added, its positive ions are attracted to the DNA's negative charges, effectively neutralizing them. This stops the fragments from adhering and keeps them floating in solution.

So, by controlling the salt concentration, anyone can make DNA fragments either disperse or clump together. And therein lies the critical secret of separating DNA from cells and manipulating it at home.

Isolating the DNA: Extraction

Here's how it works. First, you'll need a salty solution, called a buffer, into which DNA can dissolve. Next, you'll need to break open a bunch of cells and let their molecular "guts" seep out into your buffer. Then, you'll want to add a special enzyme that will destroy unwanted molecules, such as proteins, which would otherwise contaminate your results. Finally, you'll have to reduce the salt concentration enough to cause the DNA molecules to clump together and fall out of solution.

For the buffer:

Distilled or bottled water (glass 1) 120ml (about 4 oz)
Salt 1.5 grams (¼ tsp)
Baking soda 5 grams (1 tsp)
Liquid laundry detergent, dish detergent, or shampoo (glass 2) not soap — look for sodium lauryl sulfate on the label, 5ml (1 tsp)
Crushed ice to chill the buffer
Meat tenderizer
Pineapple juice, or contact lens cleaning solution just a dollop

For a source of DNA: Anything with living cells or cells preserved by freezing such as fruits, vegetables, legumes, fungi, meat from the butcher shop (a frozen cow tongue works great!), bone marrow from soup bones, etc.

To extract the DNA: Isopropyl (rubbing) alcohol (glass 3) with no additives and as concentrated as possible. Chill the bottle in the freezer before you begin.

Sundries: A drinking glass to mix the buffer, small narrow glass container (preferably with straight walls; a test tube is ideal, but a shot glass will do) to extract the DNA, narrow drinking straw to add the alcohol, a graduated test tube (or a plain one and a ruler with a centimeter scale) to measure the DNA, glass swizzle stick to remove the DNA.

Step One: Build the Buffer

First, you'll need to whip up your buffer. Pour 120 milliliters (about 4 ounces) of distilled or bottled water into a clean glass container. Add the table salt and baking soda, and stir vigorously. After they have dissolved completely, stir in the detergent. Shampoos and liquid laundry detergents that contain sodium lauryl sulfate (check the label) work well.

Next, add the meat tenderizer by wetting a toothpick, inserting it into the meat tenderizer, and transferring it to the buffer. Meat tenderizer contains an enzyme called papain that breaks up proteins so they won't come out with the DNA. Pineapple juice and contact lens cleaning solution also contain protein-busting enzymes, so, alternatively, you can add a drop of one of these 2 liquids.

Lastly, because DNA degrades fast (sometimes in a matter of minutes), you'll want to slow the pace of destruction by chilling the buffer in a bath of crushed ice. If the buffer becomes cloudy, you've chilled it too much. In that case, warm it just enough to clear it.

Step Two: Get the DNA

For a source of DNA, try the pantry. You can get great results with raw onions, garlic, bananas, or tomatoes. But it's your experiment; choose your own personal favorite fruit, veggie, meat (fresh or frozen), or fungus.

Once you've secured your DNA source, you'll need to process its cells to extract their organic molecules. First, use a knife to dice the material into small pieces. Put the material into a blender and pour in just enough distilled or bottled water to cover the chunks. Then break up (or lyse, as biologists say) the cells by pulsing the blades in short bursts until you've blended the material into a slushy mass. This will rip open some of the cells directly and expose many more cell walls and nuclei to the detergent's attack.

Finally, you need to leach out the organic molecules. Place 5ml (1 tsp) of the minced mush into a clean container. Mix in 10ml (2 tsp) of your chilled buffer. Swirl gently for 2 minutes, and the guts of the shattered cells will separate into the buffer intact. If you stir too vigorously, you'll break up some of the DNA.

Cathal Garvey in Cork, Ireland, developed this 3D printable centrifuge attachment for a rotary tool, dubbing it the "Dremelfuge." What an awesome alternative to an expensive piece of lab equipment, congrats on paving the way for DIY science! If you don't have access to a 3D printer to print your own, he's made it available for purchase on Shapeways, where it's still cheaper than a traditional centrifuge. [via @bre]

More:

Lab-on-a-Chip with Shrinky Dink and toaster oven

After trying some 50 arrangements of household objects, researchers have come up with a new low-cost, homemade bed-bug detector. To lure the bugs out of hiding, Wan-Tien Tsai of Rutgers University in New Brunswick put dry ice into an insulated, one-third-gallon jug, the kind available at sports or camping stores. Adding 2.5 pounds of dry ice pellets and not quite closing the pour hole allowed carbon dioxide to leak out at a bug-teasing rate for some 11 hours at room temperature, she said. She stood the jug in a plastic cat food dish with a piece of paper taped on the outside of the dish as a bug up to the rim. The bowl’s steep, slippery inside, with an added dusting of talcum powder, kept bugs from crawling out again. In tests in real apartments, the homemade setup detected bed bugs as well, or better, than did two brands of professional exterminating equipment, Tsai said December 16 at the annual meeting of the Entomological Society of America.

Just spotted this nifty concept by Thingiverse user cathalgarvey. He calls it a "DremelFuge." It's a centrifuge attachment for your drill or motor-tool that holds six Eppendorf tubes. Dunno how well it would actually work, as it looks heavy to mount in a Dremel tool, and most drills don't spin nearly that fast. Still, clever thinking.

A commenter on our recent DIY panoramic film camera post pointed out that the same site, Fun Science Gallery, also hosts this awesome tutorial on building a simple single-lens microscope based on the very earliest microscope technology. [Thanks, George!]

Windmil of the future? The latest advancement in kite fighting? Kitesurfing robots? The Festo CyberKite deftly controls the graceful movements of a rather large kite with relative ease. [via BotJunkie]

Neat idea from students at the University of Edinburgh, who claim to have used Tom Knight's BioBricks technology to produce a strain of bacteria that are bioluminescent in the presence of explosives or explosives residue. The notion is that liquid cultures of the bugs could be sprayed onto the ground in mined areas and would glow green wherever mines were to be found. I can think of lots of reasons why this might not work as well as one might hope, however, and because no technical details seem to be available, nor any peer-reviewed data, the news should probably be taken with a grain of salt. If anybody has any more info, please link us in the comments. [via Boing Boing]

This may be one of those situations where my love of a good story gets me in trouble with the more hard-minded scientific types among you, so please understand first that this is all intended in fun. Nonetheless, there are some intriguing facts here.

During the summer of 1997, the U.S. National Oceanic and Atmospheric Administration (NOAA) repeatedly detected an extremely powerful underwater sound on an array of Cold War era hydrophones originally installed to listen for soviet submarines. "While it bears the varying frequency hallmark of marine animals, it is far more powerful than the calls made by any creature known on Earth." Phil Lobel, a marine biologist at Boston University, purportedly "agrees that the sound is most likely to be biological in origin," although his opinion appears to be in the minority. (Both quotes from this article at CNN.com.) The approximate origin of the sound has been identified as 50 S x 100 W, which is almost exactly the same latitude as Lovecraft's fictitious sunken city of R'lyeh, at 48 S x 123 W, although it is 1000 miles distant in terms of longitude. [Thanks, Maredith!]

You can listen to a sped-up version of "The Bloop" on the NOAA website here.