| |
|
|
Issue no. 15, 2012
Published: May 25, 2012 |
|
 Rewritable DNA memory shown off | | 'Impossible' material would stretch when compressed | | Artificial immune system gives baby vaccines a booster | | Pollution-hunting robot fish take to the sea | | Important building block for quantum internet developed | | Afraid of needles? Futuristic syringe doesn't need them | | Street lights 'changing ecology on the ground' | | Zombie blondes invade Facebook with fake profiles |
|
| Rewritable DNA memory shown off |
Researchers in the US have demonstrated a means to use short sections of
DNA as rewritable data 'bits' in living cells. The technique uses two
proteins adapted from viruses to 'flip' the DNA bits.
The team from Stanford University's bioengineering department has been
trying for three years to fine-tune the biological recipe they use to
change the bits' value. The bits comprise short sections of DNA that
can, under the influence of two different proteins, be made to point in
one of two directions within the chromosomes of the bacterium E. coli.
The data are then 'read out' as the sections were designed to glow green
or red when under illumination, depending on their orientation.
The proteins, integrase and excisionase, were taken from a bacteriophage
- a virus that infects bacteria. They are involved in the DNA
modification process by which the DNA from a virus is incorporated into
that of its host. The trick was striking a balance between the two
counteracting proteins in order to reliably switch the direction of the
DNA section that acted as a bit. After some 750 trials, the team struck
on the right recipe of proteins, and now have their sights set on
creating a full 'byte' of DNA information.
As the DNA sections maintained their logical value even as the bacteria
doubled 90 times, one clear application would be in using the DNA bits
as 'reporter' bits on the proliferation of cells, for example in
cancerous tissue. But longer-term integrations of these computational
components to achieve computing within biological systems are also on
the researchers' minds. |
| BBC News / Proceedings of the National Academy of Sciences
May 22, 2012 |
 back to top
|
|
| 'Impossible' material would stretch when compressed |
Imagine cushions that lift up instead of sinking when you sit on them.
Impossible? Not according to a blueprint for new materials with
'negative compressibility': the materials compress when they are pulled
and expand when they are pushed.
Metamaterials that do this have been built before. For example,
vibrating aluminium bars with tiny cavities inside them create waves
that oppose the push or pull applied. But the designs must be vibrated
at just the right frequency to see the effect.
Researchers of Northwestern University in Evanston, Illinois, have now
designed a metamaterial that stretches when compressed, and vice versa,
under any circumstances. That should be impossible, as any material that
behaves this way would be inherently unstable and instantly collapse
into a stable state without displaying such behaviour.
The team got around this by designing a material with an internal
structure that does transition to a stable state, but a state that is
more compressed or expanded than the original state. Their theoretical
design involves a row of four 'particles' - each made of groups of
molecules - that attract each other to varying degrees. The force
attracting the two inner particles is weak, so that pulling on the
material breaks that bond. As soon as that happens, the outer particles
attract each other more, so overall the material compresses. If this
material is squeezed, though, the two inner particles are brought close
enough together to reform the weak bond - and the material can expand. |
| Nature Materials
May 22, 2012 |
back to top
|
|
| Artificial immune system gives baby vaccines a booster |
When a baby leaves the cocoon of its mother's womb, it faces a world of
potential pathogens. Now, a model of the immature immune system promises
to boost the development of vaccines designed specifically for newborns.
There are very few such vaccines at present.
A baby's immune system is distinct from an adult's, and tends to mount a
much weaker response to foreign material, including infectious agents.
While this is vital for coping with an onslaught of non-threatening
bacteria, it also means that babies are more susceptible to some
infections and don't respond as well to vaccines developed for adults.
To improve the development of vaccines for newborns, researchers of
Boston Children's Hospital in Massachusetts have created a new way of
modelling the newborn immune system. The team first took blood from
human umbilical veins and used it to culture two types of cells: those
that make up blood-vessel walls and white blood cells, which are key
drivers of the immune response. They were able to grow these cells in
the collagen matrix that in the body forms their physical and
biochemical support system by finding the ideal conditions in which to
mature the collagen. The system is topped off with newborn plasma - the
liquid component of blood.
In their latest experiment, the team found that the model responded to
the BCG vaccine for tuberculosis in the same way that newborns have in
clinical trials. The researchers reckon their model provides a reliable
way to test vaccines before trialling them in newborns. They are already
using the model to develop new adjuvants - agents that are added to
vaccines to boost their effect. |
| New Scientist
May 23, 2012 |
back to top
|
|
| Pollution-hunting robot fish take to the sea |
Robot 'fish' developed by European scientists to improve pollution
monitoring moved from the lab to the sea in a test at the northern
Spanish port of Gijon on Tuesday.
The developers hope the new technology, which reduces the time it takes
to detect a pollutant from weeks to seconds, will sell to port
authorities, water companies, aquariums and anyone with an interest in
monitoring water quality. It could also have spin-offs for cleaning up
oil spills, underwater security, diver monitoring or search and rescue
at sea, they said.
The fish, which are 1.5 metres long and currently cost USD 31,600 each,
are designed to swim like real fish and are fitted with sensors to pick
up pollutants leaking from ships or undersea pipelines. They swim
independently, co-ordinate with each other, and transmit their readings
back to a shore station up to a kilometre away.
The fish can avoid obstacles, communicate with each other, map where
they are and know how to return to base when their eight-hour battery
life is running low, their makers say. After the tests this week, the
team will look at modifications needed to move the fish into commercial
production, which they expect to reduce the cost of each unit. |
| Reuters
May 22, 2012 |
back to top
|
|
| Important building block for quantum internet developed |
Scientists at the University of Innsbruck say they've created the first
efficient and tuneable interface for quantum networks.
An interface is needed to transfer information from quantum processors
onto the photons that carry the information. Optical fibres will then
transmit them between remote data registers, probably composed of
quantum dots or ions.
The team trapped a single calcium ion in a so-called Paul trap and
placed it between two highly reflective mirrors. They excited the ion
with a laser, thereby generating a photon which is entangled with the
ion and reflected back and forth between the mirrors.
Photons bounce back and forth up to 25,000 times between these mirrors,
interacting with the ion, before escaping through one mirror into an
optical fibre. The entanglement between ion and photon can be
custom-tuned by adjusting the frequency and amplitude of the laser.
The technique has two big advantages over previous approaches that have
entangled atoms with light. The efficiency with which they produce
entangled photons is quite high and could in principle be increased to
over 99%. But above all this setup makes it possible to generate any
possible entangled state, according to the scientists. |
| TG Daily
May 24, 2012 |
back to top
|
|
| Afraid of needles? Futuristic syringe doesn't need them |
Getting a shot may soon be nearly painless, according to researchers
developing a new type of syringe. The device is able to blast a
high-pressure jet of medicine at the speed of sound through a person's
skin without the aid of a hypodermic needle.
While needle-less syringes have been around for a few years, the
prototype device MIT scientists are developing can be fine-tuned to
control the depth and speed of drug delivery. For example, a shot may
start with a super high-pressure blast to penetrate the skin, but then
scaled back to deliver the drug in a slower stream. The device can be
programmed for different types of skin.
The device can be used for delivery of drugs right through the eye into
the retina as well as the inner ear. It can also be programmed to
vibrate, which is able to make powdered drugs behave as if they were a
liquid, which means it can inject powdered vaccines in parts of the
world that lack refrigeration. |
| MSNBC / MIT
May 24, 2012 |
back to top
|
|
| Street lights 'changing ecology on the ground' |
The presence of street lights substantially changes the ecology of
ground-dwelling invertebrates and insects, research suggests. Scientists
trapped nearly 1,200 of the animals in areas under and between street
lights. They report that invertebrate predators and scavengers were more
common near the lights, even during the day. That suggests street lights
influence ecology more than previously thought.
Much work in recent years has gone into addressing the effects that
street lights can have on local, transient populations of bugs -
particularly those that can fly and have significant ranges of
exploration. But the effects of street lights on the vast communities of
invertebrates on the ground remained unaddressed.
Researchers of the University of Exeter set 28 traps in Helston in
Cornwall, some just under street lights, and some in dark regions midway
between them, over a three-night period. The team found in general that
a higher number of animals were trapped near the lights. But the
relative proportions of predators and scavengers such as beetles and
harvestmen were significantly different, with a higher proportion being
found near the lights - even during the day.
This study now seems to be indicating that those transient, nocturnal
effects on the behaviour of the animals are actually being translated
into the habitat preferences of the animals in the daytime as well,
according to the researchers. |
| BBC News / Biology Letters
May 23, 2012 |
back to top
|
|
| Zombie blondes invade Facebook with fake profiles |
Beware of the blondes. It's not life advice, but it could save you a
good deal of trouble on Facebook, where scammers, armed with pictures of
attractive blond women, are creating fake profiles specifically designed
to spread malware and steal your identity.
The zombie profiles all show blond women in their early 20s with the
same interests, the same favourite sport (cricket) and the same
favourite movie, 'Arab Spring Wedding', said Dan Tynan from PC World.
Tynan compared the fake profiles, with names such as Mandy Barnes,
Jasmine Wilson and Mindy Bennett, to one another, and found that each
girl's profile has three photos and the exact same quotation, and the
women are all friends with each other.
At first glance, the profiles appear completely legitimate; it's only
when each one is scrutinised against another similar fake profile that
the truth becomes clear - these blondes are bad news. The ruse, called
'like fraud', could make the scammers behind the zombie profiles rich,
and damage your computer and your privacy in the process.
If you accepted a friend request from one of these blond bots the owner
of the fake profile could easily exploit this new relationship by
sending you messages, pictures or a host of other files containing
malware built to steal your passwords, emails, or, in the case of a
dangerous new Facebook bug, even your bank account information. |
| MSNBC
May 22, 2012 |
back to top
|
|
|
