a population of merged white dwarfs w · artist’s rendering of the gaia spacecraft stellar...

764 24 AUGUST 2018 • VOL 361 ISSUE 6404 sciencemag.org SCIENCE

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BLOOD

A turbulent way to make platelets Donations from volunteers are

the only source of blood for trans-

fusions. But blood components

such as platelets have a shelf

life of only 5 days, and alterna-

tive sources of platelets are in

demand. By visualizing fluores-

cently tagged megakaryocytes

(precursor cells of platelets) in

transgenic mice, Ito et al. dem-

onstrated that highly turbulent

blood flow is a determining factor

of platelet production from mega-

karyocytes. Turbulence triggered

the production of thrombopoietic

factors from megakaryocytes,

which, along with shear stress,

stimulated platelet release. By

using a turbulence-controllable

bioreactor, functionally viable

platelets could be generated

from megakaryocytes derived

from human-induced pluripotent

stem cells at a quantity that

satisfies clinical-scale demand,

suggesting the possibility of de

novo platelet production as an

alternative to acquiring platelets

through blood donations. —MY

Cell 174, 636 (2018).

INFECTIOUS DISEASE

Zika in the testes: A Trojan horseZika virus (ZIKV) is a mosquito-

borne flavivirus that can also be

sexually transmitted. Although

people infected with ZIKV are

often asymptomatic, there is

an association between ZIKV

infection in pregnant women and

severe birth defects in their chil-

dren. Matusali et al. showed that

ZIKV can replicate for several

days in testicular tissue explants.

ZIKV infects testicular somatic

cells, germ cells, and spermato-

zoa, and its presence has been

detected in semen samples from

ZIKV-infected patients. Despite

Edited by Sacha Vignieri

and Jesse SmithIN OTHER JOURNALS

because of the protein’s wide-

spread role in multiple tissues

and organs. Cuchet-Lourenço et

al. studied patients with inherited

immunodeficiency of unknown

cause (see the Perspective by

Pasparakis and Kelliher). They

identified inactivating mutations

in the RIPK1 gene in four individu-

als. Unlike what has been seen

in mice, the deleterious effects

of RIPK1 loss in humans were

confined to the immune system, a

finding with potential therapeutic

implications. —PAK

Science, this issue p. 810;

see also p. 756

SOCIAL ROBOTICS

Robots help autistic kids interact with adultsChildren with autism spectrum

disorder (ASD) often struggle

with social behaviors such as

recognizing emotional responses

in others and understanding

gaze direction. Scassellati et al.

put a fully autonomous, adap-

tive robot in the homes of 12

children with ASD for 1 month to

help improve the children’s social

skills. The robot and a caregiver

engaged with each child for 30

minutes every day, playing games

that involved activities such as

emotional storytelling and taking

another’s perspective. The robot

autonomously adapted task diffi-

culty to each child’s performance

and modeled appropriate gaze

directions. The children showed

improvements in attention skills

and, crucially, demonstrated the

improvements while interacting

with adults even when the robot

was not present. —RLK

Sci. Robot. 3, eaat7544 (2018).

GAS GIANT PLANETS

Moons drive structure in Jupiter’s auroraeLike Earth, Jupiter has aurorae

generated by energetic particles

hitting its atmosphere. Those

incoming particles can come

from Jupiter’s moons Io and

Ganymede. Mura et al. used

infrared observations from the

Juno spacecraft to image the

moon-generated aurorae. The

pattern induced by Io showed

an alternating series of spots,

reminiscent of vortices, and

sometimes split into two arcs.

Aurorae related to Ganymede

could also show a double struc-

ture. Although the cause of these

unexpected features remains

unknown, they may provide a

way to examine how the moons

produce energetic particles or

how the particles propagate to

Jupiter. —KTS

Science, this issue p. 774

PROTEOMICS

The blood proteome in diseaseUnderstanding the function of

human blood serum proteins

in disease has been limited by

difficulties in monitoring their

production, accumulation, and

distribution. Emilsson et al. inves-

tigated human serum proteins of

more than 5000 Icelanders over

the age of 65. The composition of

blood serum includes a complex

regulatory network of proteins

that are globally coordinated

across most or all tissues. The

authors identified modules and

functional groups associated with

disease and health outcomes and

were able to link genetic variants

to complex diseases. —LMZ


GRAPHENE

An electronic wedding cakeIn nanostructures such as quan-

tum dots, spatial confinement

forces electrons to assume dis-

crete energy levels. Quantization

can also occur in an external

magnetic field, where electrons’

energies group into so-called

Landau levels (LLs). Gutiérrez et

al. explored the interplay between

these two mechanisms and elec-

tronic interactions in a circulator

resonator made of graphene. As

an external magnetic field was

increased, the electron quantum

states transformed from atomic-

like states to LL-like states.

Electronic interactions caused a

characteristic wedding cake–like

shape of electronic density at

high fields. —JS


Artist’s rendering of the Gaia spacecraft

STELLAR EVOLUTION

A population of

merged white dwarfs

White dwarfs are the hot

exposed cores left over when

a dying low-mass star throws

off its outer layers. The Gaia

spacecraft recently provided

accurate distances to more than a

hundred times as many white dwarfs

than were previously available, allow-

ing detailed studies of the population.

Kilic et al. investigated the mass and

composition of these white dwarfs and

reproduced them with stellar evolu-

tion models. They show that about

15% of the white dwarfs have higher-

than-expected masses. This is a sign

that they formed from mergers, either

between two parent stars or two white

dwarfs. —KTS

Mon. Not. R. Astron. Soc. Lett. 479, L113 (2018).

RESEARCH | IN SCIENCE JOURNALS

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induction of antiviral genes, no

overt inflammatory response was

observed, and testicular morphol-

ogy and hormone production

remained unaffected. Apparently,

ZIKV remains quiescent in the

testes. This phenomenon may

explain asymptomatic disease

transmission and offer a possible

target for antiviral drugs. —MY

J. Clin. Invest. 10.1172/

JCI121735 (2018).

CELL BIOLOGY

Raman spectroscopic transcriptome Raman spectroscopy records

the vibrational Raman spectra

of biomolecules, allowing the

determination of chemical spe-

cies in target samples. Although

nondisruptive and label-free, its

application in cell imaging is lim-

ited because of the complexity of

cellular compositions. Kobayashi-

Kirschvink et al. described

computational approaches to

extract key information from cel-

lular Raman spectra in yeast and

bacteria. Dimension-reduction

methods enabled a direct predic-

tion of transcriptomes from

cellular Raman spectra. A better

correlation between the Raman

spectra and noncoding tran-

scriptome revealed a more linear

correspondence of noncoding

RNAs with cellular constituent

biomolecules. Although it remains

unknown if the linkage can be

demonstrated at the single-cell

level, spectroscopic live-cell

omics provides new possibili-

ties to monitor different cellular

states. —SYM

Cell Syst. 7, 104 (2018).

EDUCATION

Teaching and research in synergyThe unspoken belief in gradu-

ate student training is that time

spent teaching, or learning about

teaching, will decrease research

productivity. Shortlidge and

Eddy tested this trade-off using

a national sample of life science

Ph.D. students. Results show

that graduate students who

participated in evidence-based

teaching (EBT) trainings did not

exhibit a reduction in confidence

in their research career, in their

ability to communicate their

research, or in their publication

number. Contrary to current

belief, the data trended toward a

slight synergy between investing

in EBT and research prepara-

tion, suggesting that institutions

can integrate EBT training into

graduate programs without

reducing students’ research

success. Additionally, invest-

ment in EBT training can better

prepare graduate students for

the multifaceted role of a faculty

member. —MMc

PLOS ONE 13, e0199576 (2018).

HIBERNATION

Snowy bat caves Snow provides thermal protec-

tion from extreme temperatures,

a phenomenon capitalized on by

polar bears and people indig-

enous to parts of the Arctic. But

snow does not provide a cozy

environment, a likely reason

why more mammals have not

evolved to take advantage of

its protection against extreme

cold. Hirakawa and Nagasaka,

however, report that Ussurian

tube-nosed bats (Murina

ussuriensis) appear to create tiny

snow “caves” with their bodies,

which then serve as opportu-

nistic hibernacula. After coming

across anecdotal accounts of

small bats being found curled up

in the snow, the authors system-

atically searched for bats in such

conditions, finding more than

30 near Sapporo, Japan. The

animals displayed classic torpor

positions, curled nose-to-tail, and

decreased body temperatures.

The authors model conditions

under which the bats’ bodies

could create their small caves

and set forth several hypotheses

for hibernating conditions and

scenarios. The finding that these

bats use a snowy blanket for

hibernation protection opens up

the opportunity for many intrigu-

ing questions to be answered.

—SNV

Sci. Rep. 8, 12047 (2018).

BIOMATERIALS

Layers of bone repairThe repair of osteochondral

defects requires proper growth

of subchondral bone, articular

cartilage, and the interface

between them, but current treat-

ments have been more palliative

than curative. Kang et al. devel-

oped a trilayer scaffold, with

variations in the architecture

and mineral environment along

its depth. The bottom layer was

enhanced with calcium phos-

phate to recruit endogenous

cells, whereas the upper two

layers were loaded with donor

cells to support stratified carti-

lage formation. When implanted

in vivo, these trilayer scaffolds

formed osteochondral tissue

with a lubricin-rich cartilage

surface. —MSL

Acta Biomater. 10.1016/

j.actbio.2018.07.039 (2018).

Ussurian tube-nosed bats hibernate in tiny snow caves.

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Snowy bat cavesSacha Vignieri

DOI: 10.1126/science.361.6404.764-f (6404), 764-765.361Science

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