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Female Anopheles albimanus mosquito feeding on a human host. This species is a vector of malaria, predominantly in Central America. Image: Wikipedia
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Issue no. 15, 2011 Published: Apr 22, 2011 |
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Scientists manipulate mosquitoes in malaria fight | Chance discovery may revolutionise hydrogen production | Apple iPhone stores data on users' whereabouts | Self-healing plastic fixed with a laser's light touch | Cooling with heat | DARPA takes new look at electrical brain stimulation |
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| Scientists manipulate mosquitoes in malaria fight |
Scientists working on malaria have found a way of genetically
manipulating large populations of mosquitoes that could eventually
dramatically reduce the spread of the deadly disease.
Researchers from Imperial College London and the University of
Washington found that after making specific genetic changes to a few
mosquitoes and then allowing them to breed on, genetic alterations could
be spread through large mosquito populations in a few generations. This
is the first successful proof-of-principle experiment of its kind and
suggests the method may in future be used to spread genetic changes in
wild mosquito populations to make them less able to transmit malaria.
The scientists showed that a modified genetic element - a homing
endonuclease gene called I-SceI - can efficiently spread through caged
populations of mosquitoes. The genetic element 'homes' to a particular
portion of the DNA where it becomes integrated into the broken
chromosome. This process - known as genetic drive - could be used to
transmit a genetic change through a population of mosquitoes that
affects the insects' ability to carry malaria.
The team bred mosquitoes with a green fluorescent gene as a marker. They
allowed these insects to mate with a small number of mosquitoes that
carried a segment of DNA coding for an enzyme which can permanently
inactivate the fluorescent gene. After each generation, they counted how
many still had a green gene. The results showed that after starting with
almost 99%t of fluorescent mosquitoes, more than half had lost their
green genes in just 12 generations. |
| Reuters
Apr 20, 2011 |
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| Chance discovery may revolutionise hydrogen production |
Producing hydrogen in a sustainable way is a challenge and production
costs are too high. But now a team at Ecole Polytechnique Federale de
Lausanne (EPFL) have discovered by chance that a molybdenum based
catalyst can be produced cheaply and efficiently at room temperature.
Water can be broken down by applying an electrical current in a process
known as electrolysis to produce hydrogen and oxygen. In order to
improve this slow reaction, platinum is generally used as a catalyst.
However, platinum is an expensive material that has tripled in price
over the last decade. Now EPFL scientists have shown that amorphous
molybdenum sulphides, abundantly available, make efficient catalysts and
hydrogen production costs can be significantly lowered.
The new catalysts exhibit many advantageous technical characteristics.
They are stable and compatible with acidic, neutral or basic conditions
in water. Also, the rate of the hydrogen production is faster than other
catalysts. The discovery opens up some interesting possibilities for
industrial applications such as in the area of solar energy storage.
The next stage is to create a prototype that can help to improve
sunlight-driven hydrogen production. But a better understanding of the
observed phenomenon is also required in order to optimize the catalysts. |
| PhysOrg / EPFL
Apr 14, 2011 |
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| Apple iPhone stores data on users' whereabouts |
The Apple iPhone might be storing detailed information about users'
whereabouts and uploading it to their computers when they synchronize
their digital devices, say two British security researchers. A program
on the smartphone records geographic co-ordinates and a time stamp,
which are then uploaded to a user's hard drive, meaning anyone with
access to that drive could determine where a person has been and when.
Pete Warden and co-researcher Alasdair Allan, announced their discovery
at the Where 2.0 technology conference in Santa Clara on Wednesday.
Allan and Warden have set up a website detailing how the information is
recorded, where it can be found and steps that can be taken to protect
the information, including encrypting the data. In a blog post on Radar
O'Reilly, a technology website, they said the data collection feature
seems to have first appeared with the release of iOS 4 in June 2010.
Allan and Wardan say the data is not transmitted anywhere else but is
normally stored in an unprotected format. It is also transferred to a
new Apple phone when that device is synched up with the computer.
'We're not sure why Apple is gathering this data, but it's clearly
intentional, as the database is being restored across backups and even
device migrations,' they wrote. Attempts to contact Apple were not
successful, and the company has not issued a statement about the claims. |
| CBC News
Apr 20, 2011 |
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| Self-healing plastic fixed with a laser's light touch |
Researchers from the US Army Research Lab in Maryland, Case Western
Reserve University in Cleveland and the University of Fribourg in
Switzerland are reporting this week that they can fix cracks in
materials with a flash of light.
Engineers have initially performed their trick using a special class of
rubber called a metallo-supramolecular polymer. Unlike regular polymers
like the polystyrene, or the clear polycarbonate that CDs are pressed
with, the molecules in the new rubbery polymers are not linked by strong
covalent bonds - which involve atoms sharing electrons. Instead, the
spaghetti-like base units of the materials terminate in 'ligand' groups
that like to link to free zinc based groups through ionic bonding. When
UV light hits these zinc groups, they absorb energy and convert it into
heat, which can be used for self-repair.
The team took a 0.4 mm-thick sheet of the polymer and gouged fissures
between 0.2 and 0.3 mm deep in it. They then fired a 1 watt UV laser at
each crack for 30 seconds - and found the fissure healed completely.
They now want to try healing a wide range of different polymers using
lasers - but they have to be careful about the mixture. 'Materials with
higher metal content healed less well,' they reported. |
| New Scientist / Nature
Apr 20, 2011 |
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| Cooling with heat |
A quantum system can be cooled with a blast of hot incoherent light.
That is the surprising conclusion of theoretical physicists who have
shown that the rate of cooling can sometimes be increased by putting a
system in contact with a hot entity.
Since the 1980s physicists have been cooling gases of atoms using
coherent laser light. This method works by having atoms absorbing and
emitting photons such that the atoms gradually lose momentum. This
technique only works if the light is coherent - if it is not coherent
the light simply heats up the gas. But now researchers of the Freie
Universitaet Berlin have come up with a way of using incoherent light to
cool a quantum system. Their system is a mechanical quantum oscillator
that is coupled to two optical modes - but can be applied to a wide
range of three mode quantum systems.
The process begins with the mechanical oscillator in a high-energy or
hot state. One of the optical modes is cold, which means that energy can
potentially flow from the oscillator to the cold mode - cooling the
oscillator. The second optical mode is hot, meaning that it contains a
large number of incoherent photons and is subject to thermal
fluctuations. According to the team's calculations, this hot mode has
two effects on the temperature of the mechanical oscillator. One effect
is obvious; the hot mode heats the oscillator. The second unexpected
effect is that fluctuations in the hot mode increase the rate at which
energy is transferred from the oscillator to the cold mode. The key to a
practical application is to ensure that the latter effect is dominant. |
| PhysicsWorld
Apr 19, 2011 |
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| DARPA takes new look at electrical brain stimulation |
New research going on in Albequerque, NM by a team of neuroscientists
working for the Defense Advanced Research Projects Agency (DARPA)
indicates that mild brain stimulation with electrical shocks, might in
fact cause people to learn more easily.
The team has been applying electrodes to the scalps of volunteers, and
then giving them very mild electrical shocks while they play a battle
simulation video game designed to teach soldiers to react properly in
stressful conditions. Called transcranial direct-current stimulation
(tDCS), the procedure employs a nine volt battery and electrodes
connected to wet sponges affixed to the temples of game players to send
just a few milliamps of current through the skull and into the brain as
they attempt to differentiate between friend and foe in dilapidated,
potentially dangerous environmental conditions.
Two groups were tested, one received 2 milliamps while they played, the
other just 0.1. The volunteers receiving the larger amount showed twice
as much improvement as those that did not. Because the amount of current
is so small, volunteers report no pain, just a slight tingling sensation
during the procedure, and afterwards can offer no real explanations as
to why they performed better than they might have otherwise. |
| Medicalxpress / PhysOrg
Apr 21, 2011 |
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