Science - USA (2021-10-29)

SCIENCE science.org 29 OCTOBER 2021 • VOL 374 ISSUE 6567 575

PHOTOS (LEFT TO RIGHT: DR. D.P. WILSON/SCIENCE SOURCE; ANT PHOTO LIBRARY/SCIENCE SOURCE

PEROVSKITES

Stable emission in glass

Lead halide perovskites can

exhibit bright, narrow band

photoluminescence but have

stability issues related to the

formation of inactive phases and

the loss of lead ions. Hou et al.

show that the black, photoac-

tive phase of cesium lead iodide

can be stabilized by forming a

composite with a glassy phase

of a metal-organic framework

through liquid-phase sintering.

The photoluminescence is at

least two orders of magnitude

greater than that of the pure

perovskite. The glass stabilizes

the perovskite under high laser

excitation, and about 80% of

the photoluminescence was

maintained after 10,000 hours of

water immersion. —PDS

Science, abf4460, this issue p. 621

PHYTOPLANKTON

Circulating in the

sunlit ocean

Marine plankton, which lie at

the base of oceanic food chains,

drive global biogeochemical

fluxes, and knowledge of their

distribution is key to under-

standing the response of oceans

to environmental changes.

Sommeria-Klein et al. explored

the patterns and drivers of

biogeography in eukaryotic

plankton using a probabilistic

model of taxon co-occurrence

to compare the biogeography

of 70 major groups, including

a variety of size fractions and

ecologies. The analysis is based

on metabarcoding data from

Edited by Caroline Ash

and Jesse Smith

IN OTHER JOURNALS

MACHINE LEARNING

Bayesian optimization

of electrocatalyst

In recent years, high-entropy

alloys (HEAs) have attracted

a lot of attention for catalytic

applications. The vast composi-

tion space of HEAs ensures the

existence of surface sites having

optimal catalytic properties, yet

such complexity represents a

great challenge for combinato-

rial approaches to experimental

catalyst discovery. Pedersen

et al. constructed a methodology

based on Bayesian optimization

combined with kinetic model-

ing and density functional

theory calculations to predict

the most active compositions

for the electrochemical oxygen

reduction reaction from the

quinary HEAs Ag-Ir-Pd-Pt-Ru and

129 stations in several oceanic

provinces worldwide. Samples

are from sunlit surface waters

and, in about half of the stations,

from the deep chlorophyll maxi-

mum. An essential message is

that small phototrophs distrib-

ute mostly by latitude and bigger

consumers are partitioned by

ocean basin. —CA

Science, abb3717, this issue p. 594

PLANT SCIENCE

Nodulation regulation

Legumes convert atmospheric

nitrogen into biologically useful

ammonium with the help of

symbiotic bacteria housed in

root nodules. Much of nodule

development is controlled by the

transcription factor NODULE

INCEPTION (NIN). Feng et al.

show that NIN is proteolytically

processed to release a fragment

that regulates the later stages

of nodulation when the nodules

acquire nitrogen-fixing capability.

In related work, Jiang et al. identi-

fied members of the NIN-like

protein (NLP) transcription factor

family as being regulators of

leghemoglobin expression acting

through an unusual promotor

motif shared across legumes.

— PJ H

Science, abg2804, abg5945,

this issue p. 629, p. 625

NEUROSCIENCE

Flipping astrocytes to

treat Alzheimer’s

Astrocytes are implicated

in b-amyloid accumulation in

Alzheimer’s disease. Raha

et al. identified an orally ingested

combination of clinically

approved drugs that induced

astrocytes to take up and break

down b-amyloid fibrils instead

of promoting b-amyloid buildup.

Astrocytes in cell cultures and in

Alzheimer’s disease model mice

were stimulated to phagocytose

b-amyloid by retinoic acid and to

degrade b-amyloid by the choles-

terol-lowering drug gemfibrozil. In

mice, the combination of retinoic

acid and gemfibrozil reduced

b-amyloid load and improved^

cognitive function. —LKF

Sci. Signal. 14 , eabg4747 (2021).

Variations in the size of marine

phytoplankton, here viewed under

a microscope, infl uence

their biogeographic distribution.

Archaeological evidence indicates that cassowary eggs were exploited by

humans in New Guinea from the Late Pleistocene to the early Holocene.

PALEOECOLOGY

Prehistoric eggshells

C

assowaries are now restricted to the rainforests of

Australia and New Guinea. They are among the few

large ratite birds to have survived the global expansion

of human populations, unlike the moas of New Zealand,

which were hunted to extinction. Douglass et al. report

archaeological evidence for human exploitation of cassowaries

in the mountain forests of New Guinea in the Late Pleistocene

and Early Holocene. Their data suggest that harvesting of

cassowary eggs may have been preferred over the hunting of

adult birds. Microstructural features of the sampled eggshells

suggest that there was preferential exploitation of eggs close

to hatching, which raises the intriguing possibility that humans

may have attempted the rearing of cassowary chicks. –AMS

Proc. Natl Acad. Sci. U.S.A. 118 , e2100117118 (2021).