New Scientist - USA (2019-11-23)

(Antfer) #1
18 | New Scientist | 23 November 2019

Disease

Moving holograms
that you can touch

IT IS possible to create a 3D moving
image using nothing but a tiny
polystyrene ball and speakers.
Ryuji Hirayama at the
University of Sussex, UK, and his
colleagues built the device using
512 speakers, positioned above and
below a small 3D stage that acts as
an image display. The speakers
emit silent ultrasound to create
small pockets of low air pressure
in which the polystyrene ball

Minute nutrient pods
could tackle poor diet

TINY particles packed with vital
nutrients could provide a better
way of delivering supplements to
people at risk of malnutrition. The
particles protect their contents
from moisture and resist heat
during cooking before breaking
down in the stomach.
Some 2 billion people globally
have nutrient-deficient diets. This
is the leading cause of cognitive
and physical disorders in the
developing world, according to an
international team of researchers
led by Ana Jaklenec and Robert
Langer at the Massachusetts
Institute of Technology.
A major challenge in adding
nutrients to food is that many are
destroyed by the heat of cooking
or add a bad taste to dishes, the
pair say. Their team has overcome
these issues by trapping nutrients
inside small, protective particles
that can be added to food.

Malnutrition^ Technology

TWEAKING the rabies vaccine could
lead to more effective and cheaper
treatment that may save some of
the 60,000 people killed by the
disease each year.
More than two in three
people live in areas where
rabies is endemic. Something
as simple as a dog bite – dogs
account for around 99 per cent of
infections – can transmit the virus,
but symptoms may not emerge for
weeks. If an infected person hasn’t
received treatment by then, death
is virtually inevitable.
Unfortunately, the vaccines used
both to prevent infection and to
treat someone with rabies are costly
and need multiple rounds to work,
which is an issue in poorer nations.
This prompted James McGettigan
at Thomas Jefferson University in
Pennsylvania and his colleagues

to search for a better treatment.
Current vaccines use the inactive
virus to trigger B cells in the body.
B cells remember the virus and
make antibodies against it to fight
any subsequent infection. The team
modified this vaccine by attaching
an extra protein to the surface of
the inactive virus, one that binds
directly to B cells and alerts them to
the existence of the pathogen more
quickly than the old vaccine does.
When the researchers tested this
vaccine on mice, they found that the
levels of antibodies in their blood
jumped quicker and higher than in
mice given the old vaccine. Within
five days, mice who had the new
vaccine had twice the level of
antibodies in their blood of the
other mice (PLoS Neglected
Tropical Diseases, doi.org/dd7x).
Ruby Prosser Scully

Improved rabies vaccine


could save more lives


floats. By manipulating the sound
waves, they can rapidly shift the
precise 3D position of the low-
pressure pockets, and so control
the position of the ball.
If the bead moves fast enough,
it traces out what appears to the
viewer to be a 3D shape, and it is
even possible to change the form
of that shape over time to give the
impression of a moving 3D object.
All this has to happen extremely
quickly. The 3D shape has to be
traced out in full in less than
0.1 seconds – any slower and
the visual effect is lost.
It is possible to add colour to the
3D objects by directing beams of
red, green and blue light onto the
bead. In one demonstration, the
system shows a butterfly flapping
its wings (pictured). People are
also able to touch the image. This
works because the speakers create
an area of higher pressure air
surrounding the bead. When your
fingers contact it, it feels like you
are touching the 3D object (Nature,
doi.org/dd72). Gege Li

The microscopic particles
measure less than a quarter of a
millimetre across and can package
11 different nutrients individually,
or combinations of up to four
nutrients together. They are
made of a material that is resistant
to heat, light and moisture, but
disintegrates when exposed to
stomach acid, ensuring that the
nutrients inside are released
and absorbed by the gut.
The researchers baked
particles containing iron into
bread, which was then eaten
by 24 volunteers. Almost three
weeks after eating the bread,
iron levels in their blood were
equivalent to levels detected
after they had a conventional iron
supplement (Science Translational
Medicine, doi.org/dd73).
Giuseppe Battaglia at University
College London says the approach
could have applications beyond
delivering nutrients: it may also
be possible to encapsulate some
therapeutic drugs using the
particles. Layal Liverpool

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