TechSmart 121, October 2013 TechSmart 132, September 2014 | Page 29

SCIENCE

Space geeks, like us, rejoiced last month as the European Space

SCIENCE
PIC OF
THE
MONTH

Agency’s Rosetta space craft finally arrived at its destination – the Comet
67P/Churyumov-Gerasimenko. This will be mankind’s first attempt at a
controlled touch-down on a comet, with five potential landing sites identified
when going to print. The Philae lander, sent from the Rosetta orbiter, is set
to make contact with Comet 67P on 11 November. The Rosetta’s journey
started way back in March 2004, with it travelling 6.5 billion kilometres to
arrive at its destination. Surprisingly the comet (4 km in length) is only 400
million kilometres away from Earth, between Jupiter and Mars
Images credit: ESA/Rosetta/NAVCAM

Can we cure neurodegenerative
diseases? It seems we might be a step

closer.

How so? According to a recent study lab-

grown nerve cells have successfully been
integrated into live brain tissue in mice. After
six months, the grafted cells had formed
functional connections with the host cells and
showed normal activity.

Why was the graft not rejected?

Neuroscientists reprogrammed skin cells
from the host to become neuronal stem
cells. This means that the host’s brain tissue
recognised the grafted cells as coming from
its own body, and so accepted the graft as
familiar.

Any clinical applications? Possibly, yes.
Parkinson’s disease develops because
dopamine-producing brain cells die. If
new, implanted cells can be spurred into
producing dopamine, the supply of this
neurotransmitter can be reset to the right
levels.
Source: bit.ly/1ufwLHh

September 2014 | TechSmart

STICKY GECKO FEET
How do geckos stay put while upside
down? It’s all thanks to physics. Scientists

previously showed that geckos have tiny
bristle-like hairs under their feet. Molecular
forces create a strong attraction between the
hair and the surface, which maximises the
contact surface.

Image: University of Twente

Life is full of questions that need smart answers. We can help.

Image: Bjørn Christian Tørrissen, CC BY-SA 3.0

NERVE CELL IMPLANTS

Image: Shutterstock

SMART ANSWERS

FREEZING WATERDROPS
How does a waterdrop freeze? From the

bottom up.

Why is this interesting? The shape of the
drop changes from rounded to conical as
freezing progresses.
What happens? Real-time video images of

But what if they need to get unstuck?

the process show that the just-frozen surface
is always at a 90º angle to the still-liquid
surface.

Does the switch take a lot of energy?

But why the shape change? Water
expands when it freezes, so ice takes up
more space than water. To keep the angle
at 90º, the freeze front becomes concave
as freezing progresses. The only way
the ice crystals can fit themselves into
this arrangement is by pushing upwards.
Combine an inward curve and an upward
push, and you get a pointy tip.

That’s where a new study comes in.
Scientists proofed that by merely changing
the angle of the hairs relative to the surface,
geckos can switch between sticky and nonsticky mode.
No. In fact, adhesion absorbs energy. But
switching to non-sticky mode recovers that
energy.

What’s next? The findings can be useful
for developing dry adhesives, which could
improve the way robots climb over rough
terrain or in extreme environments.
Source: bit.ly/1zAc1LD

What’s next? The new insight will help to
explain the effects of ice forming on aircraft
wings.
Source: bit.ly/XrZBte, http://vimeo.com/102231964

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