sciencemag.org SCIENCE

form intermolecular percolation networks for electrons. —PDS

Science, this issue p. 1391;

see also p. 1334

CELL BIOLOGY

Local control of localized protein synthesis Localized protein synthesis pro-vides spatiotemporal precision for injury responses and growth decisions at remote positions in nerve axons. Terenzio et al. show that this process is controlled by local translation of preexist-ing axonal mRNA encoding the master regulator mTOR (see the Perspective by Riccio). mTOR controls both its own synthesis and that of most newly synthe-sized proteins at axonal injury sites, thereby determining the subsequent survival and growth of the injured neuron. —SMH

Science, this issue p. 1416;

see also p. 1331

MATERIALS SCIENCE

More than just simple folding Origami involves folding two-dimensional sheets into complex three-dimensional objects. However, some shapes cannot be created using standard folds. Faber et al. studied the wing of an earwig, which can fold in ways not possible using origami and can alter its shape for flight. The

authors replicated this ability by using a membrane that allows for deformations and variable stiffness. Prestretching gener-ated energetically bistable origami patterns that exhibited passive self-folding behavior. —MSL

Science, this issue p. 1386

CANCER

For cancer, think globally, act locally Systemic immunotherapy in cancer treatment can have major side effects because it stimulates the entire immune system and is not necessar-ily tumor-specific. Surgery, a classic mainstay of cancer treatment, has the drawback of temporarily suppressing the immune response at the site of tumor resection. To address both concerns, Park et al. designed hydrogel scaffolds to gradu-ally release agonists of innate immunity. They implanted these scaffolds into mice at the sites of tumor resection. This approach was safe and more effective than systemic or even locally injected immunotherapy. —YN

Sci. Transl. Med. 10, eaar1916 (2018).

CANCER

An alternate route for metastatic cells Metastatic tumor cells are thought to reach distant organs by traveling through the blood circulation or the lymphatic system. Two studies of mouse models now suggest a hybrid route for tumor cell dissemina-tion. Pereira et al. and Brown et

al. used distinct methodologies to monitor the fate of tumor cells in lymph nodes. They found that tumor cells could invade local blood vessels within a node, exit the node by entering the blood circulation, then go on to colonize the lung. Whether this dissemi-nation route occurs in cancer patients is unknown; the answer could potentially change the way that affected lymph nodes are treated in cancer. —PAK

Science, this issue p. 1403, p. 1408

PHYSICS

A circular solution for quantum simulationQuantum simulation can map challenging problems in complex materials onto better defined ones in simpler, easier-to-manipulate systems. Physical implementations range from trapped ions to superconduct-ing qubits, each having distinct strengths and weaknesses. Nguyen et al. propose a quantum simulator that seems to combine many of the best features of the existing simulators in one system, while being within cur-rent experimental reach. The simulator is based on circular Rydberg atoms—with a highly excited electron orbiting the nucleus along a roughly circular path—where the atoms can be trapped by laser light, can be read out one by one, and have very long lifetimes. The interactions between such atoms would make it possible to simulate some of the most challenging problems in many-body physics. —JS

Phys. Rev. X 8, 011032 (2018).

The foldaway wings of an earwig

inspire materials design.

Edited by Sacha Vignieri

and Jesse SmithIN OTHER JOURNALS

PLANT SCIENCE

Natural variation in salt toleranceSalt stress in agriculture is not just a matter of being near the ocean; as much as half of irrigated farmland is overly salty. Plants have strategies to adjust to saline conditions, such as reducing sodium uptake or altering the architecture of their root systems. Julkowska et al.

analyzed a range of Arabidopsis

thaliana genotypes to identify genetic loci that could drive changes in root architecture in response to salt. Natural variation across 347 A. thaliana

accessions affected the angle of roots and the distribution of bulk between main and lateral roots, leading to identification of the genes responsible. For example, variation in gene expression in response to salt showed that the CYP79B2 (cytochrome P450 family 79 subfamily B2) gene serves to reduce lateral root growth in salt-stressed conditions. —PJH

Plant Cell 29, 3198 (2017).

RESEARCH | IN SCIENCE JOURNALS

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1374 23 MARCH 2018 • VOL 359 ISSUE 6382

Ancient forest

fragmentation is a

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OPTICAL COMMUNICATION

Faster, faster, fasterWith consumer broadband

speeds on the rise and the

prospect of “fiber to the

home” effectively providing

access to unlimited bandwidth,

actual end-user data rates

will nevertheless be limited by

the radio-frequency wireless

routers. One solution (avoiding

hardwiring) is optical

wireless communication,

whereby an optical system

replaces the wireless link. The

obvious issue is that gadgets

in a room tend to move, and a

direct line-of-sight connection

between sender and receiver

stations is required. Zhang et

al. propose an optical beam-

steering scheme that provides

a sufficiently wide field of view

and demonstrate a data rate

of 40 gigabits per second. The

ability to stream content in high

definition on multiple devices

without the “wheel of patience”

would be a thing of the past.

—ISO

Opt. Lett. 43, 723 (2018).

that there is a clear relationship

between Arctic temperatures

and severe winter weather for

the United States over the past

two decades and that severe

winter weather in the eastern

United States has become more

frequent as Arctic temperatures

have risen. Although they were

not included in the analysis, this

relationship is likely valid for

northern Europe and East Asia

as well. —HJS

Nat. Commun. 10.1038/s41467-018-

02992-9 (2018).

NEUROGENESIS

Neurogenesis and the sleeping fly As we have all experienced, the

body’s alertness, cognitive abili-

ties, and stress threshold depend

on obtaining sufficient sleep.

But why? Studies suggest that

sleep is needed to set up the right

brain connections. Szuperak et

al. looked at the earliest stages of

sleep by monitoring fruitfly larvae.

To test for periods of rest, or

sleep, they tried to arouse larvae

by exposing them to a bright light.

Fly larvae were indeed aroused

from periods of rest, and as a

result of this sleep disruption,

they slept more at a later time,

like other animals. Sleep-deprived

larvae also showed decreased

neurogenesis. This work suggests

that flies may be a model for

sleep, with possible implications

for brain development. —BAP

eLife 10.7554/eLife.33220.001 (2018).

BIOPHYSICS

Cell geometry regulates differentiationThe size and shape (geometry)

of cells regulate tension on the

cytoskeleton and the contractility

of the cell membrane. von Erlach

et al. show that mesenchymal

stem cells grown in different

shapes have varying amounts of

cell membrane microdomains

known as lipid rafts. These are

thought to be focal points for

membrane-associated signaling,

and the authors demonstrate

that their occurrence was depen-

dent on cytoskeletal contraction

and cell geometry. Activation

of signaling by the AKT kinase

occurred at lipid rafts, and this

was dependent on cell geometry

and membrane contractility.

Interestingly, AKT activation

at lipid rafts was an important

determinant of mesenchymal

stem cell lineage, once differenti-

ated. —GKA

Nat. Mater. 17, 237 (2018).

CLIMATE EXTREMES

The chill of a warming worldWhy have some winters been

so cold in some of the north-

ern midlatitudes, even though

global climate is getting hotter?

Paradoxically, the answer may

be that the Arctic itself is warm-

ing so quickly. Cohen et al. show

The blizzard Jonas of 2016, in the Bronx, New York, USA

PALEOECOLOGY

Human impact on African forests

About 2600 years ago, continu-

ous forest in western central

Africa was replaced by a

mosaic of forest and savanna.

It has been unclear, however,

whether this was caused by climate

change or expansion of the contem-

porary human population. Using

a sedimentary record of vegeta-

tion and hydrological history from

Cameroon, Garcin et al. confirm the

key role of humans in this transi-

tion. Although the pollen record

indicates an abrupt fragmentation

of the forest, there is no signature

of an accompanying hydrological

change. Nor did the hydrology alter

500 years later when the landscape

reverted once more to forest, indi-

cating a negligible role for climate.

—AMS

Proc. Natl. Acad. Sci. U.S.A. 10.1073/

pnas.1715336115 (2018).

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Human impact on African forestsAndrew M. Sugden

DOI: 10.1126/science.359.6382.1374-a (6382), 1374-1375.359Science 

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