22 January 2022 | New Scientist | 21ArthritisKNEE implants that generate a tiny
electrical current may be able to get
cartilage to regrow to treat arthritis.
Rabbits given the implants, which
make electricity from mechanical
forces as the animals move, led to
more healing after cartilage damage
than those given a placebo device.
Earlier research suggested that a
mild electric current can encourage
cartilage cells in the knee to multiply
and repair damage. Thanh Nguyen
at the University of Connecticut and
his team developed a membrane,
about half a millimetre thick, which
generates electricity when it is
compressed and stretched, to avoid
having to use bulky batteries. Thematerial is designed to encourage
cells to migrate into it.
They tested the implant by
making holes in the knee cartilage
of rabbits and patching them up
with the material. After a month of
rest, the researchers got the rabbits
to hop around for 20 minutes a day.
Two months later, they found
that cartilage cells had moved into
the patches and the joints appeared
more intact. Cartilage from these
rabbits scored 15 out of 18 on
average, while rabbits given patches
of a similar material that didn’t
generate electricity scored about 5
(Science Translational Medicine,
doi.org/hcrb). Clare WilsonElectric implants seem able to
regenerate degraded cartilage
DR
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CIENCE^ PHOTO
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YAnimal decline is
hurting plants tooThe disappearance of
birds and mammals is
bad news for plants that
rely on them to disperse
their seeds. A computer
model based on data
from 302 animal species
suggests there has been
a steep decline in the
spread of seeds tied to
historical animal losses
(Science, doi.org/hc2h).3D map of 8 million
galaxies unveiledThe largest 3D map of
the universe has been
created by the Dark Energy
Spectroscopic Instrument
in Arizona. The map, which
contains information on
8 million galaxies, will
get more detailed over the
next five years. It may help
explain the mystery of why
the universe is expanding
faster and faster.Donkey-ass hybrid
is 4500 years oldThe bones of horse-like
creatures from a Bronze
Age tomb in Syria belong
to a human-bred hybrid,
an analysis of DNA in the
remains reveals. Ancient
people crossed donkeys
and wild asses, possibly
to create animals with
the best features of both
(Science Advances,
doi.org/hc2g).PA
UL
VI
TU
CC
I
Really brief
AnthropologyMEMBERS of the Wari society
in the Peruvian Andes more
than 1000 years ago may have
mixed hallucinogenic seeds
into their beer to give it a kick.
The Wari culture flourished in
what is now Peru between around
AD 550 and 1000. Since 2015,
Matthew Biwer at Dickinson
College, Pennsylvania, and his
team have been excavating a Wari
site called Quilcapampa. The team
found a pit filled with about a
million seeds of a kind of fruit
known as molle, or Peruvian
pepper. The fruits were used to
make a fermented alcoholic drink,
a bit like beer, known as chicha.
A few steps away, in a garbage
pit, they found seeds from vilca
trees (Anadenanthera colubrina).
The seeds contain hallucinogenic
substances and have been widely
used in Andean cultures.
If you eat vilca seeds, your
stomach enzymes deactivate
the active compounds in them –
so the seeds are more normally
ground up and then snorted,
producing a strong effect.
However, chicha suppresses those
stomach enzymes, so the drink
and whole seeds taken together
would allow “a very mild and
controlled hallucinogenic effect”,
says Biwer. Michael MarshallAncients may have
spiked their beerNew Scientist Daily
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ExoplanetsTHE melting point of iron
has been gauged in conditions
similar to those in the cores of
super-Earths, planets with masses
several times that of our world.
It shows these exoplanets should
have a long-lasting magnetic field
that is thought to be necessary
for life to thrive on the surface.
A molten iron core is a feature of
many planets, including ours. On
Earth, it creates a magnetosphere:
a magnetic field that shields ourplanet from harmful radiation.
Understanding the conditions
under which iron melts can tell us
how likely it is that other types of
planet will be similarly protected
and for how long.
Richard Kraus at the Lawrence
Livermore National Laboratory,
California, and his team used
one of the world’s most powerful
lasers to recreate the pressures
found at the centre of super-
Earths. They then used diffracted
X-rays to work out whether iron
would be solid or liquid under
these conditions.
The melting temperatures thatKraus and his team measured
suggest that planets four to six
times the mass of Earth retain
liquid metal cores for the longest,
longer even than Earth will. This
means that these super-Earths
should have very long-lasting
magnetospheres (Science,
doi.org/hc2q).
However, core impurities
and confounding effects caused
by a planet’s mantle will also
have an impact on the strength
and duration of an exoplanet’s
magnetosphere, says Guillaume
Morard at the University of
Grenoble Alpes, France. AWSuper-Earths have
life-friendly shields