strength or duration decides
the developing T cell’s fate has
been a matter of much debate.
Shinzawa et al. generated
FlipFlop mice in which Cd4 and
Cd8 genes encoded co-receptor
proteins opposite of wild-type
mice. This switch resulted in a
reversal of T cell immunity with
MHC II–responsive cytotoxic
CD4+ T cells and MHC I–reac-
tive CD8+ helper T cells. These
findings argue against TCR sig-
nal strength as the operational
paradigm. Rather, Cd4 and Cd8
co-receptor gene loci appear
to determine T cell lineage fate
by regulating the kinetics and
duration of TCR signaling. —STS
Nat. Immunol. 23 , 731 (2022).SCIENTIFIC WORKFORCE
Fewer free rides,
more collaboration
All collaborations have a “social
loafer” who expends the least
effort. With collaboration
being increasingly required inhave escaped. It was believed
that no breeding populations of
the ancestors of these species
existed in the wild. However,
Chai et al. report the discovery
of a new species in a remote
protected area that is appar-
ently not a hybrid, appears to
be free from poaching, and is
reproducing at healthy levels,
realizing the value of exclusive
protected areas and commu-
nity action. —SNV
Zoo. Res. 10.24272/j.issn.2095-
8137.2022.101 (2022).
BATTERIES
Foldable solid-state
battery electrolyte
Covalent organic framework
(COF) materials have large
pore channels and high stabil-
ity and thus can facilitate
rapid ion transport. However,
lithium ion conduction is often
hampered by the size of the
channels, because the solid-
state diffusion occurs mainly
along the pore walls. Guo et al.
dissolved dimethylacrylamide
into the electrolyte lithium
bis(trifluoromethanesulfonyl)
imide that is then deposited
into a Li COF and subsequently
polymerized. The net effect was
to decouple the transport of Li+
from both the COF walls and
polymer chains, thus improving
Li+ conductivity by a factor of- The authors show that the
electrolyte can be used to make
solid-state pouch batteries that
endure repeated bending or
folding cycles. —MSL
Ad v. M a t e r. 10.1002/
adma.202201410 (2022).
IMMUNOLOGY
Mirror to T cell selection
During positive selection,
immature CD4+CD8+ T cells in
the thymus differentiate into
either CD4+ helper T cells or
CD8+ cytotoxic T cells after
receiving signals through their T
cell receptors (TCRs). Whether
TCR and co-receptor signalingtoday’s academic and research
contexts, understanding factors
that shape social loafing in
team tasks could lead to more
efficient—and less stress-
ful—group work. Gabelica et al.
examined the degree to which
goal orientation and changes
in team learning affected
social loafing. Using a sample
of undergraduate business
students, they implemented a
multiwave design and con-
ducted linear mixed-effects
modeling to show that indi-
vidual team members on teams
scoring higher on team learning
over 9 weeks of collaboration
experienced a decrease in
social loafing. Loafing ten-
dencies were also found to
be dynamic, suggesting that
implementing strategies for
maximizing team learning could
lead to fewer free rides and
more optimal collaborations.
—MMc
J. Educ. Psychol. 114 , 716 (2021).NANOMATERIALS
Tuning nanoparticle
assembly
Polymers or peptides can form
ordered arrays of nanostruc-
tures mainly through side-chain
packing effects, but inorganic
nanoparticles form superlat-
tices mainly through physical
effects such as solvent drying.
Monahan et al. explored the
effects of solvents on the
self-assembly of peptoids
(N-substituted glycine oligo-
mers) bearing CdS or CdSe
quantum dots (QDs). In aque-
ous solvent systems, the QDs
helped to stabilize intermedi-
ate peptoid morphologies and
ultimately formed multilayers
of small peptoid sheets linked
by QDs. In organic solvents,
the QDs could either facilitate
or inhibit formation, depend-
ing on the hydrophobicity of
QD-capping ligands. When
the QDs were larger than the
peptoid monomers, large hybrid
sheets formed that contained
highly ordered square-packed
arrays of QDs. —PDS
ACS Nano 10.1021/
acsnano.2c01203 (2022).SCIENCE sciencemag.org 27 MAY 2022 • VOL 376 ISSUE 6596 959