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Coming soon: LHC for molecules
Geoffrey While
IN BRIEF ‘LHC for molecules’ starts up
There’s more than one way to sex a skink SNOW skinks can base their gender on either genes or temperature. Which strategy they choose appears to depend on the weather. Ido Pen of the University of Groningen in the Netherlands and colleagues studied two clans of snow skinks, Niveoscincus greeni, living at low or high altitude in the mountains of Tasmania, Australia. The team captured pregnant skinks from each clan and allowed half of each group to lie in the sun for 10 hours per day, while the others were restricted to 4 hours. When the skinks gave birth, the scientists sexed their offspring.
Litters born to the lowland clan had a greater proportion of females after long days in the sun, compared to short days. In contrast, the sex ratio of the highland litters remained equal (Nature, DOI: 10.1038/ nature09512). This suggests that temperature drives the sex of low altitude litters, while genes determine gender further up the mountain. Pen thinks climatic pressures are behind these different systems. At low altitudes, females born early under warm conditions have more time to grow large and produce offspring, so it is advantageous for these skinks’ gender to be temperature-sensitive. At higher altitudes, however, erratic annual temperatures mean that the timing of birth may not affect reproduction rates, so the skinks rely on genes to produce a balanced sex ratio.
Electric motors to drive nanomachines A BLUEPRINT has been sketched out for the smallest ever electric motor, which could eventually be used to drive tiny conveyor belts or pumps in future nanomachines. The motor’s rotor is a long, coal-derived molecule called anthracene, which spins around an axle composed of two ethynyl units. Each end of this axle is connected to an electrode, and a third electrode – called the gate – 18 | NewScientist | 30 October 2010
is located slightly below the axle. Applying an alternating current to this gate electrode sets up an oscillating electric field that surrounds the molecular motor and, according to the researchers’ calculations, should cause the anthracene rotor to turn. That’s because anthracene possesses what is known as a dipole moment – its negatively charged electrons tend to congregate at one end of the
molecule, making the other end positively charged. These charged ends then move in different directions under the influence of the oscillating electric field (ACS Nano, DOI: 10.1021/nn1021499). Team member Jos Seldenthuis at the Delft University of Technology says the researchers are well on the way to turning their blueprint into a working engine. “Individual aspects of the design have already been verified experimentally,” he says.
CHARGED particles are easy to accelerate in the Large Hadron Collider because they respond to electromagnetic fields. Now there is a smasher for electrically neutral molecules that could help probe chemical reactions. Ammonia is a neutral molecule, but its electrons are unevenly distributed, effectively making one end positive and the other negative. Peter Zieger at the Fritz Haber Institute in Berlin, Germany, and colleagues used this asymmetry to pull a stream of ammonia around a hula-hoopsized tube. Electrodes placed around the tube generated an electric field of varying strength that guided the molecules, allowing them to whip around the tube more than 1000 times (Physical Review Letters, DOI: 10.1103/PhysRevLett.105.173001). The next step is to collide two sets of molecules travelling in opposite directions.
Probe strikes silver on the moon “BY THE light of the silvery moon” has a new meaning. NASA’s LCROSS mission, which crashed a probe into the moon in 2009, has found evidence of silver in the ejected debris. Silver in concentrations of 100 parts per billion was found in Apollo moon rocks. But spectral analysis of the LCROSS ejecta suggests silver’s concentration is higher (Science, vol 330, p 468). The difference could be down to location: the probe hit a pole while Apollo landed at lower latitudes. Robert Wegeng of the Pacific Northwest National Laboratory in Richland, Washington, says silver may behave as a volatile on the moon, with atoms evaporating and condensing onto the surface until they get stuck in a cold spot.
IN BRIEF ‘LHC for molecules’ starts up
There’s more than one way to sex a skink SNOW skinks can base their gender on either genes or temperature. Which strategy they choose appears to depend on the weather. Ido Pen of the University of Groningen in the Netherlands and colleagues studied two clans of snow skinks, Niveoscincus greeni, living at low or high altitude in the mountains of Tasmania, Australia. The team captured pregnant skinks from each clan and allowed half of each group to lie in the sun for 10 hours per day, while the others were restricted to 4 hours. When the skinks gave birth, the scientists sexed their offspring.
Litters born to the lowland clan had a greater proportion of females after long days in the sun, compared to short days. In contrast, the sex ratio of the highland litters remained equal (Nature, DOI: 10.1038/ nature09512). This suggests that temperature drives the sex of low altitude litters, while genes determine gender further up the mountain. Pen thinks climatic pressures are behind these different systems. At low altitudes, females born early under warm conditions have more time to grow large and produce offspring, so it is advantageous for these skinks’ gender to be temperature-sensitive. At higher altitudes, however, erratic annual temperatures mean that the timing of birth may not affect reproduction rates, so the skinks rely on genes to produce a balanced sex ratio.
Electric motors to drive nanomachines A BLUEPRINT has been sketched out for the smallest ever electric motor, which could eventually be used to drive tiny conveyor belts or pumps in future nanomachines. The motor’s rotor is a long, coal-derived molecule called anthracene, which spins around an axle composed of two ethynyl units. Each end of this axle is connected to an electrode, and a third electrode – called the gate – 18 | NewScientist | 30 October 2010
is located slightly below the axle. Applying an alternating current to this gate electrode sets up an oscillating electric field that surrounds the molecular motor and, according to the researchers’ calculations, should cause the anthracene rotor to turn. That’s because anthracene possesses what is known as a dipole moment – its negatively charged electrons tend to congregate at one end of the
molecule, making the other end positively charged. These charged ends then move in different directions under the influence of the oscillating electric field (ACS Nano, DOI: 10.1021/nn1021499). Team member Jos Seldenthuis at the Delft University of Technology says the researchers are well on the way to turning their blueprint into a working engine. “Individual aspects of the design have already been verified experimentally,” he says.
CHARGED particles are easy to accelerate in the Large Hadron Collider because they respond to electromagnetic fields. Now there is a smasher for electrically neutral molecules that could help probe chemical reactions. Ammonia is a neutral molecule, but its electrons are unevenly distributed, effectively making one end positive and the other negative. Peter Zieger at the Fritz Haber Institute in Berlin, Germany, and colleagues used this asymmetry to pull a stream of ammonia around a hula-hoopsized tube. Electrodes placed around the tube generated an electric field of varying strength that guided the molecules, allowing them to whip around the tube more than 1000 times (Physical Review Letters, DOI: 10.1103/PhysRevLett.105.173001). The next step is to collide two sets of molecules travelling in opposite directions.
Probe strikes silver on the moon “BY THE light of the silvery moon” has a new meaning. NASA’s LCROSS mission, which crashed a probe into the moon in 2009, has found evidence of silver in the ejected debris. Silver in concentrations of 100 parts per billion was found in Apollo moon rocks. But spectral analysis of the LCROSS ejecta suggests silver’s concentration is higher (Science, vol 330, p 468). The difference could be down to location: the probe hit a pole while Apollo landed at lower latitudes. Robert Wegeng of the Pacific Northwest National Laboratory in Richland, Washington, says silver may behave as a volatile on the moon, with atoms evaporating and condensing onto the surface until they get stuck in a cold spot.