Science-- there's something for everyone

Friday, September 30, 2011

Monkeys recognize analogies

At least, a few members of one species of monkey can recognize abstract analogies, according to research by Joel Fagot and Carole Parron of the Universite de Provence.  The fact that this type of reasoning was thought to be the sole province of humans and great apes, makes this result surprising.  The fact that it took tens of thousands of practice sessions to get 4 of the monkeys to perform better than chance on the task makes it a bit less so.

The particular type of analogy that was tested is called relational matching.  Many of you may be most familiar with this type of reasoning from standardized tests.  Car is to driver as horse is to rider.  There’s no direct connection between a car and a horse, if you only saw the word ‘car’ you’d never guess that your were supposed to think of a horse next.  You have to understand relationships and context to get the right answer.

The scientists showed baboons (species Papio papio) that had been extensively trained a touch screen displaying two objects with a specific relationship to each other.  For example, they might see a large square and a small square.  They were then given a choice of two other pairs, one of which shared the same relationship.  In this case, it might be a large circle and a small circle, or two identical triangles.  If the monkeys understand the exercise, they will select the circles.  A few of them were able to do just that.

What makes this particularly interesting is that many cognitive scientists believe that language is essential for this type of relational thinking.  If these baboons are able to employ these thought processes without any type of language, clearly that line of reasoning is wrong.

Photo of Papio papio by Atamari, 7/15/2007

Thursday, September 29, 2011

Exoplanet with two suns

Update 1/12:  The discovery of two more circumbinary planets (planets orbiting two stars rather than one) suggests that this may be a common phenomenon.

Fans of science fiction movies and books are familiar with planets that are warmed by more than one star.  Star Wars fans will be familiar with the two-sunned planet Tatooine, whereas readers will recall that the planet in Isaac Asimov’s Nightfall had six suns.  In the real world, each discovered planet has only had one sun.  Until now.

NASA’s Kepler space telescope discovered a binary pair of stars that were periodically eclipsing each other from the vantage point of the telescope.  More intriguingly, a third object was clearly passing in front of each of the stars at varying intervals.  Measurements of the four types of eclipses within the system (star one over star two, star two over star one, the third object over star one and the third object over star two) showed that the third object was indeed a planet orbiting both of the starts. 

Three Eclipsing Bodies: This artist's concept illustrates Kepler-16b, the first planet known to definitively orbit two stars -- what's called a circumbinary planet.
Credit: NASA/JPL-Caltech/T. Pyle.

The planet, Kepler-16b, is about the size of Saturn and is not expected to have a surface temperature above negative 100° Fahrenheit despite the fact that it has two suns.  This is because each of the stars is considerably smaller than our sun, and the planet orbits them beyond the distance where liquid water can form.

Don’t you love it when science fiction becomes science fact?

Wednesday, September 28, 2011

How acupuncture doesn’t work

Thus far, all the carefully controlled studies of acupuncture either have not shown that it works or have shown that it doesn’t work.  Now a new study is making the rounds, putatively explaining the mechanism behind acupuncture.  The trouble is that closer examination reveals that the study actually shows a mechanism that can’t possibly be applicable to acupuncture.

A group of researchers from Hong Kong hooked up acupuncture needles to tiny motors.  Once inserted into the skin, the motors vibrated the needles at different rates, up to 50 hz (50 times per second).  At the higher frequencies, the affected cells released calcium, triggering the release of endorphins, which in turn give pain relief.  The authors suggest that it is the release of calcium that is the mechanism behind acupuncture’s ability to relieve pain. 

One problem with this scenario is that calcium was not released when the needles were vibrated below 20 hz.  Even if acupuncturists made it habit of rapidly vibrating needles, for which there is no evidence, I guarantee that they are not spinning those needles faster than 20 times/second.  Try spinning a toothpick between your fingers yourself if you don’t believe me.

So in essence, this study shows that if acupuncture works at all (which I doubt), it isn’t by vibrational release of calcium.

Tuesday, September 27, 2011

Haploid mammalian cells

A normal mammalian cell contains two copies of each set of genes, one inherited from the mother and one from the father.  Unraveling what each gene does can be extremely complicated, especially when the two copies are dissimilar.  It would be much simpler to determine gene functions if one could work with a cell that only had one set of genes.  Martin Leeb and Anton Wutz of the University of Cambridge have managed to create just that.

Illustration of the chromosomal organization of haploid and diploid organisms.
By Ehamberg, 5/10/2010

Haploidy, (containing only a single set of genes) is known in some species, but is never normally seen in adult vertebrates.  Every cell in our bodies is diploid (with two sets of genes) except for our eggs or sperm.  Leeb and Wutz modified a technique previously used on zebrafish in which either the eggs or sperm are irradiated to remove their genetic material prior to fertilization.  The researchers successfully created haploid mouse cells for study or implantation into mouse embryos.

To be clear, the researchers did not grow up entire haploid mice, but mice containing patches of haploid cells.  This is surprisingly useful. As Wutz explains:

These embryonic stem cells are much simpler than normal embryonic mammalian stem cells. Any genetic change we introduce to the single set of chromosomes will have an easy-to-determine effect.

Monday, September 26, 2011

Yawning is for hot heads

There has been much speculation about why animals yawn.  Prevailing theories include the ideas that yawning helps to regulate 02 and CO2 levels, or that it is a purely social activity.  More recently, some researchers have proposed that yawning regulates brain temperature.  For example, studies have shown that rats yawn following increases in brain temperature.  The rapid influx of the cooler ambient air results in lower brain temperatures after the yawn.

Yawning to cool the brain would only be effective if the outside air temperature is lower than the desired brain temperature. Therefore, Andrew Gallup Of Princeton University and Omar Eldakar from the University of Arizona hypothesized that people would yawn more often during cooler weather.  This is exactly what they found. 

The researchers exposed pedestrians in differing weather conditions to pictures of people yawning, a technique known to elicit sympathetic yawns.  At 22oC (71.6oF), 45% of people yawned back, whereas at 37oC (98.6oF) only 24% of people had contagious yawns.  Air at the latter temperature would be counterproductive for cooling purposes.

Next time you see someone yawn on a cool day, you might want to offer them a cold compress rather than a pillow.

Sunday, September 25, 2011

Just for fun: Bad science icons

The Science Punk blog has a list of iconic science images that are inaccurate or flat out wrong.  My favorite is the map of the Earth.

Most of us are used to the following picture.

However, the Mercator Projection above is only one way in which the surface of a sphere can be represented on a flat piece of paper, and it's not necessarily the best way.  Notice that Greenland appears to be about the same size as Africa, when in fact it's about 15 times smaller.

Now take a look at the Gall-Peters projection.  It's still not as accurate as a globe, but it looks completely different.  And there are other projections as well.

Check out the following two representations.

Hat tip:  Not Exactly Rocket Science.

Saturday, September 24, 2011

Faster than light travel?

See updated post 1/7/12

Update: 12/11
The group at CERN has now repeated their own experiment with more rigorous controls and gotten the same result.  Nevertheless, the majority of physicists predict that FTL neutrinos will turn out to be no more than a measurement error.  Further tests are underway.

Yes folks, physicists may have found evidence of faster-than-light (FTL) travel.  Before you start preparing for your trip to Alpha Centauri, a couple of caveats are in order.  First, the evidence for FTL travel is based on one set of experiments, albeit bridging three years of work. The data must be repeated and confirmed by other researchers, during which time other explanations may be found.  And second, the things putatively doing the FTL traveling are neutrinos.  There is no evidence that FTL travel could be applicable to anything larger than these subatomic particles. 

That said, if true, the impact of this discovery cannot be overstated.  For starters, it could mean overthrowing Einstein’s theory of special relativity.

The experiment itself was straightforward enough.  Physicists at CERN (near Geneva) fired neutrinos through the ground at a particle detector in Italy, 730 kilometers away.  On average, the neutrinos arrived about 60 nanoseconds (billionths of a second) faster than a photon of light making the same trip.  It sounds simple enough, an ordinary rate equals distance divided by time problem.  However, it’s important to keep in mind that at these speeds, tiny discrepancies can really add up.  For example, suppose the distance traveled is off by just a few meters?  Or that the start time for the neutrinos leaving CERN was miscalculated by a couple of nanoseconds?  These tiny corrections could account for the 60 nanosecond apparent lead the neutrinos have over light.

Needless to say, many physicists are skeptical of the FTL claim.  You can read more about it here and here.  

Friday, September 23, 2011

Will a satellite land on your head?

You will probably miss your chance to get hit by a piece of NASA’s UARS (Upper Atmosphere Research Satellite), which is expected to re-enter Earth’s atmosphere early Saturday morning, UTC (universal time coordinated, or Greenwich mean time).  Although most of the satellite will burn up harmlessly, two dozen or so pieces are expected to make their way to the ground.  As of this writing, the UARS is predicted to hit somewhere in the South Pacific. 

If you’re reading this post before the satellite lands, you can get updates from NASA here.  You can also read about satellite re-entry.  

So, what are your chances of being hit by the debris?  Very slim even if you happen to be in a rowboat in the Pacific Ocean at exactly the right time.  The risk that any particular person will be hit is less than one in a trillion. 

 UARS orbit history

UARS orbit history
Credit: NASA

The UARS was launched in 1991 with the purpose of studying Earth’s atmosphere.  Among its missions was the study of the photochemistry of the ozone layer and of UV and visible light.  It was decommissioned in 2005.

You can see video of the satellite tumbling down to Earth and read more about the satellite on the Planetary Society and Bad Astronomy blogs. 

Thursday, September 22, 2011

Gamers crack AIDS puzzle

A breakthrough in AIDS research has come not from the lab, but from the gaming community.  The three-dimensional structure of the protease (protein-chopping enzyme) in an AIDS-like virus has now been solved.

One of the hardest problems in biology is to predict what a protein will look like based on its amino acid sequence.  Each protein folds into a precise complicated three-dimensional shape that is critical for its function.   Solving the shape often leads to a greater understanding of that function, and in some cases, to the ability to disable the protein.  For that reason, researchers are keen to tease out the structure of proteins.  Enter, Foldit.

Foldit is a multiplayer protein-folding game complete with opportunities to compete and cooperate, and to compare rankings. Unlike other citizen science programs, Foldit does not passively make use of computer down time, but rather engages the players to actively solve the problems.  Firas Khatib of the University of Washington set Foldit players the challenge of solving the structure of a protein (part of a virus that causes AIDS in monkeys) that had stumped biochemists for the past 15 years.  The gamers (most of whom have little science background) managed to crack the structure.  In three weeks.

Read more about it at Not Exactly Rocket Science.

Wednesday, September 21, 2011

Dinofuzz in amber

Ryan McKellar and his colleagues from the University of Alberta made an intriguing discovery in the collections of Canadian museums.  Eleven of the 4000 chunks of amber in storage contained bits of feathers and protofeathers, and a handful of those can’t be identified as belonging to any living creature.

The small scraps of amber, mostly less than a centimeter across, were formed about 78 million years ago, well after the first feathered dinosaurs, or non-avian dinosaurs if you prefer.  The feathery structures may very well belong to a dinosaur, though without other features such as bone fragments preserved alongside, it’s difficult to say.

You can see a slide show of the amber-embedded feathers along with commentary here.

Tuesday, September 20, 2011

Aerial dispersal of snails

About three million years ago, the isthmus of Central America arose separating the Pacific from the Atlantic oceans.  Even at only 50 kilometers across at the narrowest point, you might think this an insurmountable barrier for marine snails. You’d be correct for snails traveling under their own power, but not for snails employing the services (and intestinal tracts) of shorebirds, from which they emerge unscathed a surprising percentage of the time. How often did this interocean transfer occur?  According to researchers from the Smithsonian Tropical Research Institute, UCLA and UC Santa Barbara, only twice.

The researchers compared the mitochondrial DNA of horn snails on both the Pacific side (from California to Panama) and on the Atlantic side (Texas to Panama) of central America. In conjunction with molecular dating techniques, the data suggest that gene flow between the two sides occurred on just two occasions, first from the Pacific to the Atlantic 750,000 years ago, and again in the opposite direction about 72,000 years ago.

1940, the paleontologist George Gaylord Simpson dubbed these kinds of unlikely events ‘sweepstakes dispersals’.  In some cases, especially on remote islands, a single fluke transfer of new species (by bird or storm) can completely alter an ecosystem forever.

More information at Not Exactly Rocket Science.

Original artwork by Kayla Orlinsky.

Monday, September 19, 2011

Pascalize your food

You read that right.  Not ‘pasteurization’, a process that uses heat to kill germs, but ‘pascalization’, which does a similar job by using extreme pressure.  The protocol, more conventionally known as high-pressure processing (HPP), has been around for almost a decade. HPP can safely kill microbes not only in fruit, but also in liquids and processed foods. The pressure kills microbes by altering their molecular structure.

More recently, Carmen Hernandez-Benes and her colleagues from Technologico de Monterrey, Mexico have shown that HPP can also improve the nutritional value of some foods. They presented their results at the 242nd National Meeting & Exposition of the American Chemical Society.

The researchers subjected avocados, mangos and papayas to between 40,000 and 80,000 pounds of pressure per square inch for three minutes, standard operating procedure for HPP.  Despite the fact that this amount of pressure is equivalent to that of a grey whale doing a pirouette on a postage stamp, the fruit was not obliterated. This is because the pressure is evenly exerted over all surfaces. Surprisingly, the carotenoid levels in the pascalized avocados and papayas increased by over 50%.  It’s not clear why this occurred, or why the mangos did not show a similar increase in antioxidants.

By the way, just as pasteurization was named after Louis Pasteur, so pascalization was coined for Blaise Pascal, who was known for his studies of pressure. 

Sunday, September 18, 2011

Another weird star

An international team of cosmologists has discovered a star with some unusual properties. SDSS J102915+172927 has the lowest concentration of elements heavier than helium (collectively called ‘metals’ by astronomers) ever found.  In fact, the star’s ‘metallicity’ is so low that it defies the previously convention for star formation.

Let’s go back in history a bit.  Soon after the Big Bang, the early universe consisted of hydrogen, helium and traces of lithium.  All other elements were created within stars, and then disseminated throughout the universe as those stars blew up in supernovas.  Since stars form by accumulating whatever material is around them, and the very oldest stars only had those three elements to hand, they have a low metallicity.  On the other hand, newer stars form from the remnants of supernovas, and have a much higher number of heavy elements.  Because SDSS J102915+172927 has almost no metals, it is assumed to be about 13 billion years old, or close to the age of the universe itself.

That’s not the weird part. Not only does SDSS J102915+172927 have almost no metals, but it also has 50 times less lithium than the post-Big Bang universe. Where did the lithium go?  Add in the fact that the earliest stars were mostly massive and short-lived, whereas SDSS J102915+172927 is only about 0.8 solar masses and obviously still around, and you have a real mystery.

The composition of a star that should not exist

An ancient star in the constellation of Leo (The Lion), called SDSS J102915+172927, has been found to have the lowest amount of elements heavier than helium of all stars yet studied. The pie-chart shows the star’s composition: it is almost entirely made from hydrogen and helium with only a tiny trace of heavier elements.
Credit: ESO/Digitized Sky Survey 2

Saturday, September 17, 2011

Just for fun: Brains in sand

The University College London (UCL) Institue of Cognitive Neuroscience hosted a "brains on film" competition.

Here's the entry by Zarinah Agnew's.

Friday, September 16, 2011

Direct ancestor of genus Homo

The two million year old Australopithecus sediba has been extensively studied since its discovery in 2008.  Now a team of anthropologists at the University of Witwatersrand and colleagues from around the world have made the case that A. sediba is our direct ancestor.

Five separate papers analyze different aspects of A. sediba’s physiology and behavior. Here are some of the highlights.

Hands:  In A. sediba, anthropologists found the most complete hominin hand to date.  It retains the strong grasping muscles essential for climbing trees, but has relatively short fingers and a long thumb like humans.  The researchers speculate that it would have been capable of making and using tools.

Australopithecus sediba has a relatively long thumb. The hand suggests that he may have had the capacity to manufacture and use complex tools.
Credit: University of Zurich; Peter Schmid.

BrainA. sediba’s brain was only about the size of a chimpanzee’s brain, but was organized in a similar fashion to that of modern humans.

Pelvis:  The pelvis plays a critical role in the hominin lifestyle and physiology.  Not only does the pelvis determine the stance (bipedal or horizontal), but it also limits the brain size of newborn infants.  A. sediba had a pelvis that was broader and more vertically oriented that earlier Australopiths.  As A. sediba did not have large brains, the change was clearly not driven by increased brain size.

Foot:  The A. sediba foot and ankle was a mix of ape and human-like features, indicating that it spent time in the trees, but could also walk bipedally.

You can read more about these discoveries at The Loom.

Thursday, September 15, 2011

Another reason to exercise

According to a study by researchers at McMaster University, exercise directs stem cells in marrow to become bone rather than fat.  Besides decreasing the amount of fat within the bone marrow cavities, this leads to improved blood production and circulation.

The scientists compared mice that ran on treadmills three times a week, less than an hour each time, with mice that were completely sedentary.  Even though the exercising mice were putting in less than three hours a week at the gym, their bone marrow cavities had less fat than those of their sedentary cohorts.  The authors suggest that the exercise was influencing stem cells to become bone cells rather than fat cells.  This leads to a cascade of effects, including improved blood circulation.  In contrast, the bone marrow of sedentary creatures slowly fills with fat cells, which impede blood production and circulation.

According to Gianni Parise:

Exercise has the ability to impact stem cell biology. It has the ability to influence how they differentiate.

Original artwork by Kayla Orlinsky.

Wednesday, September 14, 2011

Another way to find planets

Exoplanets are now almost mundane.  Hundreds have been found in just the past few years.  What makes Kepler-19c unique is not that it orbits a star other than our sun, but the way it was found.  Its presence slightly alters the orbit of a fellow planet that had already been discovered.

The planet Kepler-19b was discovered orbiting the star Kepler-19 by, wait for it, NASA’s Kepler space telescope. The Kepler telescope locates planets using the ‘transit’ method.  That is, it looks for the periodic dimming in a star’s light as a planet passes directly in front of that star.  Kepler-19b was found by this method.  However, Kepler-19b doesn’t transit its star exactly on time.  Instead, it crosses its star up to five minutes early or late each time it goes around.  That doesn’t sound like a lot, but something has to account for the discrepancy.  That something is an unseen second planet (Kepler-19c) whose gravity is ever so slightly tugging on Kepler-19b.

The "invisible" world Kepler-19c, seen in the foreground of this artist's conception, was discovered solely through its gravitational influence on the companion world Kepler-19b - the dot crossing the star's face. Kepler-19b is slightly more than twice the diameter of Earth, and is probably a "mini-Neptune." Nothing is known about Kepler-19c, other than that it exists.
Credit: David A. Aguilar (CfA)

Other than the fact of its existence, little is known about Kepler-19c.  It doesn’t transit Kepler-19 from our vantage point, and it has no detectable gravitational effect on that star. 

As Daniel Fabrycky of the University of California, Santa Cruz says:

[Kepler-19] could be a rocky planet on a circular 5-day orbit, or a gas-giant planet on an oblong 100-day orbit.

By the way, the planet Neptune was discovered in a similar fashion when astronomers attempted to explain aberrations in Uranus’s orbit.  

Tuesday, September 13, 2011

Transplanting a beating heart

Abbas Ardehali and his colleagues at UCLA are testing a device that sustains donated hearts in a beating, near-physiological state.  This innovation could revolutionize heart transplantation.

Since the dawn of heart transplantation, donor hearts have been maintained in ice chests while awaiting transplant into a recipient.  Needless to say, this method has some drawbacks, not the least of which is the limited time a non-beating heart can survive on ice. In contrast, the beating hearts in this study were placed in an Organ Care System (OCS) developed by TransMedics.  The OCS not only maintains the heart at body temperature, but also perfuses the beating heart with oxygen and nutrient-rich blood.

The doctors at UCLA and other sites are currently comparing OCS hearts to icebox hearts in 128 matched heart recipients.  If safety and efficacy tests support the beating heart method, doctors predict that it will have several key advantages.  First, hearts will be viable for longer than the six-hour limit placed on iced hearts, meaning that a donated heart can travel a longer distance to find its recipient, and that doctors can take more time to assess the heart and avoid rejection.  Second, the already beating donated hearts will not need to be warmed and restarted. And finally, the hearts may undergo less trauma in the OCS than in a cooler.

Hat tip:  Skepchick.

Monday, September 12, 2011

Sutureless blood vessel repair

Geoffrey Gurtner and his colleagues from Stanford University have tested a new way to reattach severed blood vessels.  Rather than relying on needle and thread, they used thermoreversible poloxamer and a bioadhesive. The former holds the vessels open while the latter glues the ends together.

Although sutures still work very well in many applications, they do have drawbacks.  For one thing, there is a lower size limit for a stitchable repair area.  For another, the suturing itself can cause localized trauma which can lead to obstructed blood flow at that point.  And finally, using discrete stitches of any kind allows for the possibility of leakage around the stitches.  Using adhesives can eliminate all these shortcomings.  However, you need something to keep the blood vessels fully dilated both during and after sticking the ends together, which is where the poloxamer comes in.

A poloxamer is a type of polymer gel composed of units with hydrophobic centers and hydrophilic ends. The scientists used the thermoreversible Poloxamer 407, which is solid above body temperature but liquifies at body temperature.  Using a halogen lamp to heat and solidify the poloxamer, the researchers successfully propped rat blood vessels open with the gel long enough for an adhesive to seal the vessels.  At that point, the gel was allowed to cool and dissolve away into the blood stream.

Both the sealant (Dermabond) and the poloxamer are already FDA approved for other uses.  Nevertheless, more animal studies most be done before the researchers can progress to human trials. 

Sunday, September 11, 2011

Breastfeeding brings out the tiger mom

Mammalian mothers who are nursing their young exhibit heightened aggression against threats to themselves or their babies.  This reaction is termed ‘lactation aggression’, or sometimes ‘maternal defense’.  Not surprisingly, considering that humans are mammals, women display a similar reaction. 

Jennifer Hahn-Holbrook and her colleagues from UCLA gave a computerized time-reaction test to a group of volunteers, including 18 nursing mothers, 17 formula-using mothers, and 20 non-mothers.  They each had to compete against an extremely rude rival, who was actually a confederate of the researchers.  Each time one of the women won a round, she was allowed to punish her antagonist by delivering a sound blast.  The nursing mothers blasted their rude competitors twice as loudly and for twice as long as the non-nursing women.  In addition, the breastfeeding mothers’ blood pressure remained lower than the non-lactating women during the entire exercise.  This correlates well with the observation that lactation suppresses the fear response in non-human mammals.

As Hahn Holbrook concludes:

[Breastfeeding] may be providing mothers with a buffer against the many stressors new moms face while at the same time, giving mothers an extra burst of courage if they need to defend themselves or their child.

Saturday, September 10, 2011

Just for fun: Dance your Ph.D.

UPDATE Oct. 22, 2011:  A team from the University of Western Australia in Perth won the top prize with their submission entitled 'Microstructure-Property relationships in Ti2448 components produced by Selective Laser Melting: A Love Story'. You can see it at the bottom of this post.

Don't miss your chance to enter the "Dance Your Ph.D." contest, sponsored by TEDxBrussels.  You can read the rules here.  Remember, your entry must be in by October 10th.  To get the creative juices flowing, take a look at last year's winner, presented by the DeRosa Lab from Carleton University. Use the link above if it doesn't play here.

Hat tip:  Pharyngula.

Microstructure-Property relationships in Ti2448 components produced by Selective Laser Melting: A Love Story from Joel Miller on Vimeo.

Friday, September 9, 2011

Preserve a few key areas to save marine mammals

The bad news:  at least a quarter of the marine mammals left on Earth are facing extinction.  The good news:  preserving just 4% of the oceans and other bodies of water could protect them.  Sandra Pompa and Gerardo Ceballos from Universidad Nacional Autónoma de México amd Paul Ehrlich from Stanford University have identified 20 key sites for marine mammal conservation.

There are 129 species of marine mammal, including not only whales and seal, but also polar bears and otters.  Actually, perhaps they should be called ‘water’ mammals, because six of the species live in freshwater.  In any case, the authors created range maps for each species and determine which areas of the globe were most critical to its survival.  Just nine sites making up a total of 2.5% of the surveyed regions were home to 108 of the species.  And where are these precious sites? Off the coasts of Baja California in Mexico, eastern Canada, Peru, Argentina, northwestern Africa, South Africa, Japan, Australia, and New Zealand.  Add in the other eleven sites, and you have protected at least 10% of the habitats of all 129 species.

Thursday, September 8, 2011

Bad news for spring fresh sheets

The scented products we put in our washers and dryers are coming out of the dryer vents and it’s not good news for us or for the environment.  According to a study led by Anne Steinemann at the University of Washington, fragranced laundry products lead to the venting of over 25 different volatile organic compounds (VOCs), some of which are highly toxic.

The researchers used two different residential washer/dryer units, and thoroughly cleaned them out with vinegar and repeated rinse cycles.  They then loaded the units with pre-rinsed new organic cotton towels and ran each through three types of cycles: with no products, with scented detergent, and with both scented detergent and scented dryer sheets. Air quality measurements were taken inside the dryer vent opening.  As I said, the news was not good.

Among the VOCs emitted from the scented loads were seven hazardous air pollutants, including acetaldehyde and benzene, both carcinogens with no safe limit.  This extremely limited study did not examine different types of fragrances or products (dryer sheets versus liquid fabric softener, for example).  However, in the interim, Steinemann recommends choosing unscented products wherever possible.

Wednesday, September 7, 2011

First use of blood cells from stem cells

A team of French scientists and doctors has successfully injected blood cells derived from hematopoietic stem cells (HSCs) into a living human.  This first of its kind study answered two questions:  whether cultured red blood cells could mature inside a body, and if the resulting cells would survive long enough to be useful.  Although it’s still early days, the answer to both questions seems to be ‘yes’.

The experiments were conducted in two phases.  First, the scientists collected HSCs from a donor, and used them to generate billions of cultured red blood cells (cRBCs).  These cRBCs were injected into mice. Because the cultured cells had been radioactively labeled, the scientists were able to confirm that the cRBCs continued to mature properly.  Next, the researchers repeated the experiment with HSCs from a different donor, but this time they injected the resultant cRBCs back into that same donor.  After 26 days, about half the injected cells were still viable, consistent with the 28 day half-life of natural red blood cells.

Being able to produce blood cells abundantly and without risk of infection or rejection would be an enormous advantage.  Imagine donating a few cells prior to a surgical procedure, and then knowing that a large supply of your own blood cells was waiting for you, in case of need.  

Tuesday, September 6, 2011

Transparent mice

Atushi Miyawaki and his colleagues at the RIKEN Brain Science Institute have developed a new reagent that can make biological samples transparent.  The aqueous reagent, dubbed ‘Scale’, renders most tissues transparent without altering their shapes.  In addition, Scale does not interfere with fluorescent labeling.

Caption: Mouse embryos. Left: embryo placed in phosphate buffered saline (PBS) after fixation with 4 percent paraformaldehyde (PFA). Right: embryo incubated in ScaleA2 solution for 2 weeks after fixation with 4 percent PFA.
Credit: RIKEN
Miyawaki and his team are currently using Scale to study mouse brains and neurons.  However, they are not oblivious to the myriad other uses their new reagent has.  In fact, they are working on creating similar reagents that are mild enough to use on living tissue.  Maybe I’ve read too much science fiction, but I’m picturing a doctor painting a swab of reagent on a patient’s chest to look at his heart.  I’m pretty sure that’s not how it would work though, more's the pity.

Monday, September 5, 2011

To restore lynx, bring back wolves

At first, this article seemed counterintuitive to me.  After all, aren’t wolves and lynx competitors?  Wouldn’t lynx benefit from the removal of wolves from their territories?  William Ripple of Oregon State University and his colleagues from that institution, the University of Washington and the University of Wyoming have a different take.  They believe that the reintroduction of wolves will actually help lynx recover from near extinction.

The hypothesis goes like this:  wolves are the top predators in any region in which they find themselves.  When they are abundant, they keep the population of prey animals and of lesser predators, such as coyotes, in check.  Without wolves, the coyote population and the ungulate (deer) population explode.  These two groups either consume or outcompete rabbits and hares, which are the main food of lynx.  Thus, the extirpation of wolves from an area has a negative affect on the lynx population.  The authors suggest testing this idea by examining the effect of reintroducing wolves into areas known to contain lynx.

Sunday, September 4, 2011

A light lunch for weight loss

One way to lose weight is to eat a light lunchAccording to David Levitsky and Carly Pacanowski of Cornell University, this holds true even if the other meals of the day are not restricted.  Contrary to popular opinion, most people do not compensate for a light lunch by eating more than usual for dinner.  Thus, their daily calorie consumption decreases when they eat less at lunchtime.

The researchers provided all weekday food for 17 volunteers for five weeks.  During two of those weeks, lunches were restricted for calorie content, but the subjects were free to eat as much as they liked for all other meals and snacks.  During the restricted weeks, the participants consumed about 250 fewer calories per day, leading to a weight loss of about half a pound per week.

I do have some reservations about this data.  I suspect that when people know that everything they eat will be weighed and recorded, they don’t grab a second piece of pie after dinner even if they’re ‘allowed’.  In other words, the subjects of this study may have been restricting all their meals to some extent.  Still, there was a clear daily calorie reduction associated with eating lighter lunches.  

Saturday, September 3, 2011

Just for fun: Ants!

Scientists from the California Academy of Sciences are creating a catalog of highly detailed pictures of ants. They hope 'AntWeb' will one day include all 12,000 known species. Here's one example, from the genus Ancyridris.

If you go to the slideshow, you can see each ant in various views (head, side, top, and bottom).