New Scientist - 09.7.2019

18 | New Scientist | 7 September 2019

Genetics

Low-energy nanotube

chip says ‘hello world’

A MICROCHIP made from carbon

nanotubes can outperform

modern chips when it comes

to energy efficiency. If it can be

scaled down, it could save a vast

amount of energy.

Computer performance is

improved by making silicon

electronics smaller, but that

process is slowing down, says

Max Shulaker at the Massachusetts

Institute of Technology. He and his

Deepwater Horizon oil

spill still hitting sea life

IT WASN’T just the coastline

and the ocean surface that

was drenched in oil after the

Deepwater Horizon spill in 2010.

Life in the deep sea took a hit, too,

and many species in the region are

still drastically reduced in number.

“The health of our overall

oceans also requires a healthy

deep sea, as the deep oceans

serve vital roles in carbon cycling,

marine food webs and overall

ocean function,” says Craig

McClain at the Louisiana

Universities Marine Consortium.

He and his colleagues used

remotely operated underwater

vehicles to survey the Gulf of

Mexico around the site of the

disaster. They did the survey in

June 2017 and compared their

findings with surveys done in the

two months after the oil spill.

While the number of animals

increased in that time, the

Marine biology Computing

DO YOU need 8 hours of sleep a

night or, like Margaret Thatcher

reportedly did, can you get by on

four? We have now found a gene

that dictates how much sleep you

need by studying a family that gets

by on much less than average.

Ying-Hui Fu at the University

of California, San Francisco, and her

colleagues looked at 12 members

of a family who sleep as little as

4.5 hours per night without feeling

tired. They found they had a

mutation in a gene called ADRB1.

When the team bred rats with

the same mutation, these slept

about 55 minutes less per day

than non-engineered rats. This

correlated with altered activity in a

brain region called the dorsal pons,

which is known to regulate sleep.

In the dorsal pons of unchanged

rats, ADRB1-expressing brain cells

were inactive during most sleep

stages, but active when the animals

were awake. In engineered rats, the

cells were even more active during

waking hours (Neuron, doi.org/c9zr).

Fu’s team found they could wake

sleeping rats by activating these

ADRB1-expressing brain cells.

The results suggest that

ADRB1-expressing brain cells

promote wakefulness, and that

variations in the ADRB1 gene

influence how long we can stay

awake, says Fu. Her team has

previously found that mutations

in some other genes also make

people need to sleep less.

The mutations don’t seem linked

to negative effects. “Most natural

short sleepers are very happy about

their sleep pattern – they usually

fully take advantage of their extra

time,” says Fu. Alice Klein

DNA mutation lets people

thrive on just 4 hours’ sleep

team have made a microprocessor

that sits atop a silicon wafer but

is made with carbon nanotubes

(pictured). If you used the

nanotubes to make a computer

chip with the same architecture as

silicon chips, it would be 10 times

as efficient, says Shulaker.

Carbon nanotubes are only a

nanometre thin, so such a chip

can be turned on using very

little energy. They are also good

conductors of electricity.

The team has used the chip to

run a simple program that outputs

the message “Hello, World”,

commonly the first program

written by people learning to

code (Nature, doi.org/c9zs).

“With silicon, the fabrication

temperature is 1000°C or higher,

but these carbon nanotube

transistors can be made at

essentially room temperature,”

says team-member Christian Lau.

The next step would be

to shrink the components,

allowing them to charge and

discharge faster. CW

diversity dropped. McClain says

he and his team noticed an

absence of sea cucumbers, fly-trap

anemones, Venus flower basket

sponges and giant isopods –

crustaceans that look like large

woodlice (Royal Society Open

Science, doi.org/c9zp).

There has also been a change

in which animals inhabit the area.

The team found an abundance

of arthropods, including shrimps

and crabs. McClain says they may

be attracted to the site because the

hydrocarbons that break down in

the wake of an oil spill can mimic

the chemicals in sex hormones

that they use to find mates.

“This seems to be common

in some other oil spills. A historic

oil spill in Buzzards Bay in New

England attracted the American

lobster in droves,” he says.

The animals seem to die

there, perhaps because the

chemical signals also deter

other animals they prey on

from entering the area, he says.

Chelsea Whyte

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