RESEARCHSCIENCE sciencemag.org
Water can efficiently reach the
upper atmosphere when Mars is
in the warmest part of its orbit,
and this behavior may have con-
trolled the overall rate at which
Mars lost its water. —KTS
Science, this issue p. 297
THERMAL CONDUCTIVITY
Thin graphite gets
cool fast
In nonmetallic solids, heat is
transported primarily through
crystal vibrations called pho-
nons. These phonons can have
wavelike properties under cer-
tain conditions, which increases
the thermal conductivity of the
material. Machida et al. found
that making graphite samples
thin expands the hydrodynamic
regime from cryogenic to room
temperatures. The researchers
measured an extremely high
thermal conductivity in the very
thin graphite samples, which
may be important for a variety of
electronics applications. —BG
Science, this issue p. 309
INFECTION
Why cholera is
noninflammatory
Ingestion of food or water
contaminated by the bacte-
rium Vibrio cholerae results in
cholera, which is a fatal disease
if left untreated. V. cholerae
releases toxins that translocate
effector domains into infected
cells, one of which induces
cytoskeletal damage. Using
human intestinal epithelial cells,
Woida and Satchell found that
proinflammatory signaling that
would otherwise be activated
by cytoskeleton damage was
suppressed by other effector
domains. These results may
explain why cholera is a nonin-
flammatory disease. —AMV
Sci. Signal. 13 , eaaw9447 (2020).
17 JANUARY 2020 • VOL 367 ISSUE 6475 262-C
Published by AAAS