18 | NewScientist | 17 September 2018For new stories every day, visit newscientist.com/newsA machine to split
the electronSURF’S up! Electrons riding a plasma
wave can be accelerated to high
energies, which may let us build
small particle accelerators to smash
them up and learn more about the
tiniest objects in the universe.
The world’s largest accelerator,
the Large Hadron Collider at the
CERN particle physics laboratory
near Geneva, Switzerland, smashes
protons by whizzing them around
a 27 kilometre ring, but that won’t
work for electrons – they have to
be accelerated in a straight line.
The Advanced Proton Driven
Plasma Wakefield Acceleration
Experiment, also at CERN, gets
round this by shooting hundreds of
billions of protons into a tube filled
with rubidium atoms that have been
stripped of their electrons, forming
a plasma. This results in waves in
the plasma, and when electrons
are injected into the tube,
the waves accelerate them.
The container used is just
10 metres long, and the electrons
at the end reached energies of
2 gigaelectronvolts (GeV) (Nature,
doi.org/gd3zfz).
Electrons are fundamental
particles, meaning we think they
don’t break down into anything
smaller. But we don’t know for
sure. To test that would require
smashing electrons at hundreds
of GeV, which could be done
using higher-energy protons.Print with sound using honey as ink
PRINTERS that use sound waves may
one day let us build structures out of
honey droplets, or even print human
tissue without harming cells.
Regular inkjet printers are great
at controlling the placement and
size of ink droplets, but only work
for watery fluids. Daniele Foresti at
Harvard University and his colleagues
have come up with a way to print
droplets of viscous liquids.
Inkjet printers rely on streams of
liquid naturally separating into drops.
To make droplets from a viscous fluid,
that fluid has to be forcefully broken.
The team turned to sound waves,which can exert a force on objects.
Their printer extrudes a droplet
from a nozzle and then fires sound
waves at it to make it fall to the
printing surface.
The sound is extremely loud,
but it is at a high frequency that
the human ear cannot detect.
The researchers tested the printer
using water, honey and a liquid mix
of gallium and indium metal. They
also tried an ink full of human cells to
confirm they wouldn’t be killed by the
sound (Science Advances, doi.org/
ctjq). “With the cells, you could do
tissue engineering,” says Foresti.AN ARTIFICIAL intelligence
system called Revolver is
unveiling the evolutionary tricks
cancers use to spread and defy
treatment. It should allow
doctors to more accurately
identify what stage cancers have
reached, what they will do next
and how to stop them.
We can treat cancer if we
intervene early enough, says
Andrea Sottoriva of the Institute
of Cancer Research in London,
whose team is developing Revolver.
“The key is, can you stay one step
ahead of the disease?” he says.Revolver helped Sottoriva’s
team unmask key evolutionary
steps in cancers. It uses data from
patients to create a genetic
“family tree” tracking how cancer
evolves, and identifies the series
of mutations that most often lead
to cancer. Existing analyses, often
relying on samples from one
patient, can struggle to
distinguish important mutations
from harmless ones.
Revolver instead analysed
mutation data from 178 patients,
covering 768 tumour samples and
four types of cancer – bowel, lung,breast and kidney. This made
key evolutionary steps stand out
better. Three key gene mutations
are known to be crucial for benign
colon polyps to turn cancerous,
for example, but have not been
seen together in a single patient.
Despite this, Revolver identified
the three mutations as the key
ones when tested on gene profiles
from 95 colorectal cancer patients.
It also correctly identified key
mutations already known to drive
evolution of lung, breast and
kidney cancers (Nature Methods,
doi.org/cthk).AI could help doctors stay one step ahead of cancer
MS drug halves loss
of brain tissueAN EXPERIMENTAL drug for the
most severe forms of multiple
sclerosis has slowed brain
shrinkage by nearly 50 per cent.
Loss of brain tissue is a marker
of disease progression in primary
and secondary progressive MS.
In these forms of the disease,
the ongoing breakdown of the
protective myelin that surrounds
nerve fibres in the brain leads to
slower nerve signals, which can
ultimately result in muscle
weakness and problems with
balance and vision.
Robert Fox at the Cleveland
Clinic in Ohio led a phase II
clinical trial of a drug called
ibudilast, which inhibits proteins
that can result in central nervous
system inflammation.
The trial involved 255 people
from the US, with 126 receiving a
placebo instead of the drug. Each
took up to 10 capsules per day for
22 months and had brain scans
every six months to gauge the
volume of brain tissue.
The team found that, on average,
ibudilast slowed brain shrinkage
by 48 per cent compared with
placebo, with those given the drug
losing 2.5 millilitres less brain
matter (New England Journal
of Medicine, doi.org/ctf2).CERN
DANIELE FORESTI, JENNIFER A. LEWIS, HARVARD UNIVERSITYIN BRIEF