Transplantation of pancreatic islet cells derived from human pluripotent stem cells is a promising treatment for diabetes. Despite progress in the generation of stem-cell-derived islets (SC-islets), ...no detailed characterization of their functional properties has been conducted. Here, we generated functionally mature SC-islets using an optimized protocol and benchmarked them comprehensively against primary adult islets. Biphasic glucose-stimulated insulin secretion developed during in vitro maturation, associated with cytoarchitectural reorganization and the increasing presence of alpha cells. Electrophysiology, signaling and exocytosis of SC-islets were similar to those of adult islets. Glucose-responsive insulin secretion was achieved despite differences in glycolytic and mitochondrial glucose metabolism. Single-cell transcriptomics of SC-islets in vitro and throughout 6 months of engraftment in mice revealed a continuous maturation trajectory culminating in a transcriptional landscape closely resembling that of primary islets. Our thorough evaluation of SC-islet maturation highlights their advanced degree of functionality and supports their use in further efforts to understand and combat diabetes.
Abstract
In our Galaxy, light antinuclei composed of antiprotons and antineutrons can be produced through high-energy cosmic-ray collisions with the interstellar medium or could also originate from ...the annihilation of dark-matter particles that have not yet been discovered. On Earth, the only way to produce and study antinuclei with high precision is to create them at high-energy particle accelerators. Although the properties of elementary antiparticles have been studied in detail, the knowledge of the interaction of light antinuclei with matter is limited. We determine the disappearance probability of
$^{3}\overline{{{\rm{He}}}$$
3
He
¯
when it encounters matter particles and annihilates or disintegrates within the ALICE detector at the Large Hadron Collider. We extract the inelastic interaction cross section, which is then used as an input to the calculations of the transparency of our Galaxy to the propagation of
$^{3}\overline{{{\rm{He}}}$$
3
He
¯
stemming from dark-matter annihilation and cosmic-ray interactions within the interstellar medium. For a specific dark-matter profile, we estimate a transparency of about 50%, whereas it varies with increasing
$^{3}\overline{{{\rm{He}}}$$
3
He
¯
momentum from 25% to 90% for cosmic-ray sources. The results indicate that
$^{3}\overline{{{\rm{He}}}$$
3
He
¯
nuclei can travel long distances in the Galaxy, and can be used to study cosmic-ray interactions and dark-matter annihilation.
The pT-differential cross sections of prompt charm-strange baryons Ξc0 and Ξc+ were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy s=13 TeV with the ...ALICE detector at the LHC. The Ξc0 baryon was reconstructed via both the semileptonic decay (Ξ-e+νe) and the hadronic decay (Ξ-π+) channels. The Ξc+ baryon was reconstructed via the hadronic decay (Ξ-π+π+) channel. The branching-fraction ratio BR(Ξc0→Ξ-e+νe)/BR(Ξc0→Ξ-π+)=1.38±0.14(stat)±0.22(syst) was measured with a total uncertainty reduced by a factor of about 3 with respect to the current world average reported by the Particle Data Group. The transverse momentum (pT) dependence of the Ξc0- and Ξc+-baryon production relative to the D0 meson and to the ςc0,+,++- and Λc+-baryon production are reported. The baryon-to-meson ratio increases toward low pT up to a value of approximately 0.3. The measurements are compared with various models that take different hadronization mechanisms into consideration. The results provide stringent constraints to these theoretical calculations and additional evidence that different processes are involved in charm hadronization in electron-positron (e+e-) and hadronic collisions.
New ferroelectrets were developed on the basis of foams from cyclo-olefin polymers and copolymers. The results obtained on the cyclo-olefin polymer foam demonstrate a significant improvement of the ...service temperature for ferroelectret transducer materials. Suitable compounding and preparation led to cyclo-olefin ferroelectrets with an electromechanical activity of around 15 pC/N, which is thermally stable at least up to 110degC. The properties in sensor and actuator applications are strongly dependent on the processing parameters related to film-making, sensor and actuator preparation, gas content and electric charging. The processing window for the film stretching was very narrow compared to the earlier developed polypropylene ferroelectrets. The film porosity, softness and thus the electromechanical activity are adjusted by gas-diffusion expansion. The activity of the electromechanically operating sensors and actuators was increased by stacking several layers of cellular cyclo-olefin film. For applications such as flat loudspeakers, the foamed films are tuned by tensioning them on a support frame. Correct tensioning was essential also for reducing the distortion levels
Abstract
There is an urgent need to apply effective, data-driven approaches to reliably predict engineered nanomaterial (ENM) toxicity. Here we introduce a predictive computational framework based on ...the molecular and phenotypic effects of a large panel of ENMs across multiple in vitro and in vivo models. Our methodology allows for the grouping of ENMs based on multi-omics approaches combined with robust toxicity tests. Importantly, we identify mRNA-based toxicity markers and extensively replicate them in multiple independent datasets. We find that models based on combinations of omics-derived features and material intrinsic properties display significantly improved predictive accuracy as compared to physicochemical properties alone.
A
bstract
The
p
T
-differential production cross sections of prompt and non-prompt (produced in beauty-hadron decays) D mesons were measured by the ALICE experiment at midrapidity (
|
y
|
<
0
.
5) in ...proton-proton collisions at
s
= 5
.
02 TeV. The data sample used in the analysis corresponds to an integrated luminosity of (19
.
3
±
0
.
4) nb
−
1
. D mesons were reconstructed from their decays D
0
→
K
−
π
+
, D
+
→
K
−
π
+
π
+
, and
D
s
+
→
ϕ
π
+
→
K
−
K
+
π
+
and their charge conjugates. Compared to previous measurements in the same rapidity region, the cross sections of prompt D
+
and
D
s
+
mesons have an extended
p
T
coverage and total uncertainties reduced by a factor ranging from 1.05 to 1.6, depending on
p
T
, allowing for a more precise determination of their
p
T
-integrated cross sections. The results are well described by perturbative QCD calculations. The fragmentation fraction of heavy quarks to strange mesons divided by the one to non-strange mesons,
f
s
/
(
f
u
+
f
d
), is compatible for charm and beauty quarks and with previous measurements at different centre-of-mass energies and collision systems. The
b
b
¯
production cross section per rapidity unit at midrapidity, estimated from non-prompt D-meson measurements, is
d
σ
b
b
¯
/
d
y
y
<
0.5
=
34.5
±
2.4
stat
−
2.9
+
4.7
tot
.
syst
μb. It is compatible with previous measurements at the same centre-of-mass energy and with the cross section pre- dicted by perturbative QCD calculations.
Experimental results are presented on event-by-event net-proton fluctuation measurements in Pb–Pb collisions at sNN=2.76 TeV, recorded by the ALICE detector at the CERN LHC. These measurements have ...as their ultimate goal an experimental test of Lattice QCD (LQCD) predictions on second and higher order cumulants of net-baryon distributions to search for critical behavior near the QCD phase boundary. Before confronting them with LQCD predictions, account has to be taken of correlations stemming from baryon number conservation as well as fluctuations of participating nucleons. Both effects influence the experimental measurements and are usually not considered in theoretical calculations. For the first time, it is shown that event-by-event baryon number conservation leads to subtle long-range correlations arising from very early interactions in the collisions.
A
bstract
The transverse momentum (
p
T
) differential cross section of the charm-strange baryon
Ξ
c
0
is measured at midrapidity (|
y
|
<
0.5) via its semileptonic decay into e
+
Ξ
−
ν
e
in pp ...collisions at
s
= 5
.
02 TeV with the ALICE detector at the LHC. The ratio of the
p
T
-differential
Ξ
c
0
-baryon and D
0
-meson production cross sections is also reported. The measurements are compared with simulations with different tunes of the PYTHIA 8 event generator, with predictions from a statistical hadronisation model (SHM) with a largely augmented set of charm-baryon states beyond the current lists of the Particle Data Group, and with models including hadronisation via quark coalescence. The
p
T
-integrated cross section of prompt
Ξ
c
0
-baryon production at midrapidity is also reported, which is used to calculate the baryon-to-meson ratio
Ξ
c
0
/
D
0
= 0
.
20 ± 0
.
04
stat
.
−
0.07
+
0.08
(syst
.
). These results provide an additional indication of a modification of the charm fragmentation from e
+
e
−
and e
−
p collisions to pp collisions.
The multiplicity dependence of the pseudorapidity density of charged particles in proton–proton (pp) collisions at centre-of-mass energies
s
=
5.02
, 7 and 13 TeV measured by ALICE is reported. The ...analysis relies on track segments measured in the midrapidity range (
|
η
|
<
1.5
). Results are presented for inelastic events having at least one charged particle produced in the pseudorapidity interval
|
η
|
<
1
. The multiplicity dependence of the pseudorapidity density of charged particles is measured with mid- and forward rapidity multiplicity estimators, the latter being less affected by autocorrelations. A detailed comparison with predictions from the PYTHIA 8 and EPOS LHC event generators is also presented. The results can be used to constrain models for particle production as a function of multiplicity in pp collisions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
Two-particle angular correlations are measured in high-multiplicity proton-proton collisions at
s
= 13 TeV by the ALICE Collaboration. The yields of particle pairs at short-(∆
η
∼ 0) and ...long-range (1
.
6
<
|∆
η
|
<
1
.
8) in pseudorapidity are extracted on the near-side (∆
φ
∼ 0). They are reported as a function of transverse momentum (
p
T
) in the range 1
< p
T
<
4 GeV/
c
. Furthermore, the event-scale dependence is studied for the first time by requiring the presence of high-
p
T
leading particles or jets for varying
p
T
thresholds. The results demonstrate that the long-range “ridge” yield, possibly related to the collective behavior of the system, is present in events with high-
p
T
processes as well. The magnitudes of the short- and long-range yields are found to grow with the event scale. The results are compared to EPOS LHC and PYTHIA 8 calculations, with and without string-shoving interactions. It is found that while both models describe the qualitative trends in the data, calculations from EPOS LHC show a better quantitative agreement for the
p
T
dependency, while overestimating the event-scale dependency.
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